To many of us, we'd never dream of attacking anyone in uniform, but to some, when they wanna fight they wanna fight.
Such thing happened in Time Square, NYC when a man was being arrested (for what, I don't know) and then decided he wanted to fight back against the police officer.
It's never a good idea to fight a cop, it's an even dumber idea to then mess with a New Yorker while fighting a cop...you'll end up like that guy, with a knee in your neck!