Completely disagree with your first comment. His actions didn't rise to the level of a response from the police that would lead to serious bodily injury...which is what happened. On the other hand, I don't think anyone could have foreseen a simple shove like that resulting in what happened. Kind of an "unintended consequences" thing. I don't think a simple shove by officers in a skirmish line in a high risk area is unwarranted when they're approached by someone who's obviously a little agitated.
I agree with the second part about getting into fights. Hell...just walking down a flight of stairs with my physical issues is risk enough.