The average cop is a piece of shot coward. All of a sudden he has power behind him and that badge on his chest gets real heavy and he busy black leather gloves and gets to thinking he's a hard man.
But, you know, there are a ton of laws protecting cops. They are more protected than the California Condor. This fuels the tough guy fantasies; tough guys don't fight back because it costs 10 years.
When it was a misdemeanor to hit a cop they routinely got beat up.