Starfleet Captain
Super Freak
You find out your teammate you had a falling out with is risking their life for a notorious assassin who also killed your mother, I think you'd be pissed too.
Most of the film he wasn't as he doesn't even find that out until the end. Plus its not like he doesn't have a good reason to be upset. He's fighting against his teammates to begin with and on top of it finds out that Cap is not only protecting Bucky but also that Cap knows Bucky killed Tony's parents and withheld that information. I think I'd be pretty upset too.
I understand perfectly that he is very angry and upset about 1) this friend of my teammate kills my parents 2) this teammate knew it but didn't tell me. Those are perfectly valid reason to be uber mad. I just want to remember a Tony that is heroic and nice, rather that being angry and vengeful, that's all...