Tony is the only one who deliberately takes his anger out on others
This theory seems true. Tony doesn't just take his anger out on others, but all of his emotions. He's a jerk to Hammer and Killian for no reason except Tony is bored or a jackass. He makes snarky remarks about people's trauma for the same reason, and is cruel to Steve because Tony resents Howard. Tony shoots up a party because he's depressed. OUt of anger, Tony shoots Sam when Sam has no weapons drawn, and chooses to humiliate Peter instead of mentor him on multiple occasions. Plus Tony's cold-blooded murder attempt on Bucky.
The Hulk does take his anger out on whatever is in the area, but until Ragnarok he doesn't seem to have the intelligence to know better. And none of the other characters are as self-centered and uncaring of people as Tony.
What if someone was allowed to point that out?
Note: Set after Iron Man 2 in an AU where Rhodey didn't steal a suit, just used it to restrain Tony.
***
The psychiatrist folded her hands on her desk and said, "Perhaps we can start again. Why were you ordered to undergo this evaluation?"
Tony replied, "Because some people can't take a joke."
The doc lifted her eyebrows and said, "You call shooting live weaponry in a crowded room a joke?"
Tony shrugged.
The doc leaned back in her chair and said, "So is it a joke because you're amused when you hurt other people? Or is it a joke because it was YOU who did it and you didn't take it seriously?"
Tony said, "You don't understand. I was DYING. Slowly, of palladium poisoning."
The doc replied, "And therefore your actions should be ignored?"
Tony got up and said, "And therefore I shouldn't be held responsible for my actions."
The doc sat up and said, "You are mistaken, Mr. Stark. Your actions are your responsibility. You chose to get drunk. You chose to put on weaponized armor. You fired weapons into a crowded room. And you refused to stand down and fought with Colonel Rhodes."
Tony pointed at the doc and said, "Why isn't Rhodey sitting in jail for stealing MY property?"
The doc replied, "Because Colonel Rhodes returned the armor as soon as you were neutralized."
She continued, "Do you believe that with counseling you can find more appropriate means of dealing with your emotions and the stresses of your life?"
Tony sat back down and said sullenly, "I am who I am, take it or leave it. I feel like making me sit here listening to you is cruel and unusual punishment."
The doctor nodded, then made some notations in a file and stood up. "Mr. Stark, I am declaring you competent to stand trial. I also warn you that if you attempt any defense based on mental defect, I will testify for the prosecution to contradict any such claim. You were fully cognizant of your actions and the potential harms. You deliberately ignored the danger and potential damage."
As the doctor left the office, she said, "You are a danger to those around you. I suggest you consider counseling, whether you are acquitted or incarcerated."
***
Tony was sentenced to several years in jail. Hank Pym was the one helping Bruce find the scepter. Rhodey knocked Loki on his butt in Stuttgart. Thor wasn't provoked, so there was a quick alliance. The scepter wasn't able to distract the Avengers on the helicarrier, so Clint's breakout of Loki failed. The portal was never opened and the Chitauri never invaded. Loki was persuaded to tell everyone about Thanos, and Thanos was stopped before he got a single Infinity Stone.
Tony did get counseling, eventually. But he was banned from ever using the Iron Man armor again.