Well, I hate Tony because he's a war profiteer (but uwu he felt bad about it and stopped selling weapons so everything's okay now), and never provided aid to the people who were affected by his weapons. He only stopped after being directly affected, and when he saw Americans being affected by it.
He treated Peter terribly. he stalked him for months (i'm guessing it was months), locked himself in peter's room with him, blackmailed him, kidnapped him, didn't tell him why he was fighting, neglected him, installed an instant kill mode in his suit, etc. then, when tony didn't listen to peter, peter then had to go try and stop the vulture's men himself. he made a mistake, like all people, and tony yelled at him. he physically got in peter's space and backed him up. he then took away peter's suit, probably knowing that peter wouldn't stop, giving him a bigger chance of being hurt. he was only nice to peter when peter's accomplishments affected him positively.
now, onto his murderbots. he made ultron, (bruce helped him, but tony pressured bruce so it is mostly tony's fault) and then he acted like it was a team effort, as if he didn't practically beg bruce to keep it a secret from everyone. then, in endgame, he told steve that he was right and ultron would have protected them, evidently not remembering the time when ultron tried to kill everyone. even if ultron didn't try to commit mass genocide, he wouldn't have been able to protect them from thanos. the avengers tore the ultron bots apart easily, and thanos beat the avengers just as quickly.
accords time! now, do i really need to explain why these are wrong? apparently! they require every person with superpowers (inhumans, enhanced, etc.) to give them a DNA sample, wear a tracker, etc. this is EVERYONE with powers. meaning KIDS. not just the avengers! tony can take his suit off. he can choose when and where the accords apply to him. people like steve, wanda, bucky, peter, bruce, and thor don't get that options. they can't turn their powers on and off. tony (and ross) then go to guilt the rest of the team for things that mostly weren't their fault. new york? they stopped shield from nuking the city and loki from invading. sokovia? mainly not the team (as a whole)'s fault. they had to get rid of the city so it didn't wipe out everyone, getting as many people as possible off as they could. lagos? wanda stopped WAY more people from dying. the bomb was in a crowded marketplace, and around 200 people would have died, including steve and wanda. she unfortunately lost control and the bomb went into the side of a building, killing 14 instead. none of the avengers could have brought the casualties down that low.
oh! i almost forgot. there's a section in the accords that states, and i quote, "for the purposes of the Accords, an "enhanced individual" is defined as any person, human or otherwise, with superhuman capabilities. This includes individuals whose powers are an innate function of their biology as well as individuals who utilize highly advanced technology to grant themselves superhuman capabilities. However, individuals with enhanced prostheses do not seem to be considered "enhanced" even if their prostheses give them capabilities beyond those of ordinary humans." Now, the arc reactor powers his suit. Therefore his suit counts as a prosthetic. It started out as a prosthetic, and the public knows this. Because of Iron Man 3, we now he no longer needs this to live. However, the public (meaning everyone but Tony, Pepper, and maybe Rhodey and Happy) does not. So his suit is a prosthetic. So the Accords don't apply to him. (I don't think it's the same for Bucky since he also has a version of the serum as well as his arm)
now, i shall talk about his bigotry! in iron man 1, he makes a homophobic and transphobic joke that could have cost rhodey his career.
"Tony Stark: Speaking of manned or unmanned, you gotta get him to tell you about the time he guessed wrong at spring break. Just remember that, spring break, 1987. That lovely lady you woke up with.
James Rhodes: Don't do that!
Tony Stark: What was his name?
James Rhodes: Don't do that.
Tony Stark: Was it Ivan?
This person Tony is talking about is either a trans woman or trans man (I'm pretty sure it's a trans woman). Assuming it's a trans woman, he calls her by her deadname (Ivan), and also misgenders her. He also says this in a pretty homophobic way, implying that it's gross to be with a man of youre a man. He says this in front of a bunch of Rhodey's colleagues, and this little comment could have cost Rhodey his career. This is also why it's so harmful to the lgbt community to headcanon him as queer or trans, because he's canonically queerphobic and transphobic! He sexualizes Natasha, among many other women, the minute he sees her. And do I even need to go into the islamophobia?? He only stops selling weapons after he sees that non-Americans are getting them. Which is pretty dumb, because if you don't check to see who's getting your weapons, people you're prejudiced against have a good chance of getting them. then he makes multiple rape jokes. But yeah, he's definitely a feminist (he says "I will be reinstating prima nocta" when trying to lift thor's hammer, and tells vanko that he'll send him a bar of soap in jail, aka saying he hopes vanko gets raped. Like what the fuck dude)
And he also showed no signs of caring about who died in Sokovia until an American woman told him about the one (1) American who died. Then he's all, "oH sWeEtIe PeOpLe DiEd BeCaUsE oF uS!!!!" he also called Wanda (a person) a WMD (an object), and said/implied that since she's not a US citizen, she didn't matter.
Hey look, I remembered more about the Accords! Tony tried manipulating Steve into signing the Accords by using Howard's pens and Bucky. He only failed because he mentioned Wanda, who he locked up. Yes, Steve replied with saying that she's a kid. This is different from Peter's situation because Wanda is legally an adult, if only barely.
Oh yeah, then he attacked the longest standing PoW! That's so nice of him!
Then in Infinity War, the Avengers literally lost because of his ego. The Russos confirmed that if the Avengers all fought together, they would have won. Steve couldn't come out of hiding to try and recruit Tony because he would have been arrested and Thanos would still have won. Tony didn't have anything stopping him except his pride. He then ignored Strange's wishes to go back to Earth when Strange has more knowledge than him about the stone and how to protect it. He arrogantly thought that he, Peter, Strange, other Peter, Mantis, Drax, and later Nebula could take Thanos on alone.
Now onto Endgame. He gets back to Earth and tells Steve that Ultron would have worked (see previous argument) and that Steve wasn't there for him. But guess what? That's Tony's fault! He tried stripping them of their human rights, then never called to meet Steve so they could stop Thanos. Oh, forgot to mention. It was originally scripted for Tony to admit that was right, but RDJ changed it. But, like OP asked, this essay is not about why I hate RDJ, it's about Tony Stark. He then goes to live with Pepper and Morgan, which would be nice if he hadn't abandoned the remaining half of the universe to pick itself up, providing no help. Then, when offered the chance to bring back all those people, he refuses. Why? Because he "had a life already" or something. Let me rephrase. He didn't get personally affected by the snap (the person who was "closest" to him was Peter, who he constantly neglected, and one could argue that his behaviour was abusive), so he refused to help the trillions of others who were.
Almost forgot! He constantly belittles Steve (actually everyone on the team, but mainly Steve) and makes fun of his trauma. Capsicle?? Really?? You're gonna take one of the most life-changing events in his lif that traumatized him and make fun of him for it?? Then, when Steve says he understood a reference, he rolls his eyes. Steve was two weeks out of the ice and happy to finally know something, and what does Tony do? Roll his eyes and bring Steve back down. Not to mention in the same movie, he tells Steve there's nothing special about him that didn't come from the serum. Remember this was right after Steve woke up and was at his lowest. You've gotta do better than that.
Now he also treats Pepper and Harley terribly in Iron Man 3. He puts multiple suits on guard that nearly attacked Pepper in her sleep. Like you'd think someone like Jarvis could alert him in someone was intruding instead of having a system that could-and almost did-kill his girlfriend. But even that wasn't enough, because he told terrorists his home address, aka where Pepper lived! Now it may be surprising, but telling terrorists who hate your guts your address is not smart and puts people in danger! How romantic! My point is proven right when said terrorists blow up the house that he, Pepper, and Maya were in. He also takes Harley's stuff and makes fun of him, a kid, for not having the greatest stuff. Maybe it didn't occur to him but kids that live in garages probably aren't billionaires. He then calls Harley a pussy for missing his dad. Tony, your dad didn't leave, he died and you were 21. Your situations do not compare.
Now onto Killian. He wanted revenge because he had good ideas that Tony completely blew off, not even giving him a chance to speak. Unsurprisingly, he did this to fuck around with another woman. This is pretty similar to how he treats his employees at SI. If he treated them nicely, Homecoming and Far From Home never would have happened. Tony took away Adrian Toomes's opportunity to work and best support his family. Toomes then stole weapons (and tbh who would want to steal from the white cishet rich bitch who doesn't care about you and took your job) because he thought that was the way he could put dinner on the table.
He also stole work from his employees. Remember B.A.R.F.? Yeah, that was Beck's. Beck made that, and Tony took it and presented it as his own, then firing him. He probably did the same to countless others, but we don't know them because they didn't decide to do something about it and become the villain of an mcu movie.
And remember Project Insight 2.0 aka EDITH? There's so many fucked up things about that. First, he expected Peter (a child) to be the next Iron Man (an Avenger). Like?? What?? First Civil War now this?? Tf?? Then he gave EDITH (ai with the power to kill anyone on sight) to Peter (still a child) without giving him any info on what it is or how to use it. But yeah, great dad! And obviously, Peter is overwhelmed and hands it to the first person he thinks he should: Beck. Then this goes wrong (hey Tony, that's your fault) because of course it does.
How is EDITH like Project Insight? Well, people in group chat who will scream at me for this soon, I'll tell you. Project Insight was made of three helicarriers that had enough guns to kill 3 million people in one go. This goes wrong because it's in Hydra's hands. EDITH was an ai with drones that had the (I'm assuming) same firepower, as well as projectors that could deceive anyone. This ends up with Beck. See what I mean?
And yes, he has PTSD. But so does... every Avenger? And for some reason all I see is Tony stans blaming everything on other characters or Tony's PTSD. Having PTSD doesn't mean you have no control over whether you build murderbots or not.
He then exposed Clint's family to Ross. What the shitting dammit man.
And finally, he shot Sam Wilson in the chest when Sam dodged a shot from the Mind Stone that could have killed him. It hit Rhodey, who had full body armor, and they were really high in the air. Rhodey was paralyzed! Imagine what could have happened if it hit Sam. He has no armor, so if the shot didn't kill him, the fall had a good chance of doing that. Sam is a paramedic, he could have helped Rhodey. But nope, Tony shoots him point-blank in the chest. (If you can't tell, I cant forgive anyone for shooting Mr. Sam Wilson, Captain America, our king)