Personally, I find it a bit frustrating that a large portion of people refer to the 'Politicians' as a single group. Sure some politicians are corrupt, but you shouldn't simply call all politicians corrupt. I'm sure some, at least, are somewhat good.

The problem I find with arguments such as yours is that you're looking at the few exceptions to the norm and not the trend of policing in America. Yes, there are likely a few good police organizations just like there are likely a few good cops or a few good politicians. But the point is that when the institution as a greater whole is corrupt, then it calls into question even the few good people that remain complicit in its existence. You should be demanding answers from even the good apples and making sure they stay good, not give them a pass because they haven't gone bad yet.