People are trying to justify this, really?
As a human, if I were a cop and some "liberal punk" yelled insults at me, the thought of body checking him into a sidewalk would never cross my mind. The kid has a family and a life of his own and an action like that could've sent him into the pavement head first, possibly causing death or a life-altering injury.
Come on.. especially as cyclists, you should not justify this crap. It was a cheap shot by a man who should be out of his job.