I am not opposed to laws against the violent either. The problem is that cops have quotas to fill and their job is to enforce the law. Not the US Constitution, but the statuatory law. I know there are well meaning cops, but if you really want to change things, I don't see how joining the enforcement class is helpful. I've said the same thing about the military. If they tell you to go, you either go or you go to prison, neither of which is a good thing as far as stopping the endless wars are concerned. And as a cop, you are required to enforce the law as written, even if you don't agree with it. For what its worth, I took a law enforcement class a few years ago, and that is essentially what the instructor told me as well.
The prevailing attitude these days is "change the law if you don't like it." People fail to explain how aggression is justified just because a politician wrote some scribbles on paper.
Also, I've never seen a so called "good cop" bring a bad one to justice. They all mostly look out for each other.
The system is broken. You can't fix it by joining it.