Steve takes things like personal responsibility and respect seriously. Tony's got people he pays to take care of that kind of thing, and anyway, he's pretty sure that he's going to die of some exotic disease in his workshop, because Dummy's still a little spotty about what is 'clean' enough to put on an open wound. The rest of the Avengers are in this for personal gain, except for Clint, he just enjoys being a dick. And some things shouldn't be a chore.

Sometimes Tony Stark makes poor choices. Sometimes Tony pushes his teasing of Steve Rogers just a little too far. Sometimes Steve decides he's had enough. Phil Coulson's the one who's got to write this nonsense up, and he does not bake.