I will observe one thing and you can tell me if I'm wrong.
The cops I know and have interacted with are very good people, a far larger percentage than in the world as a whole. However there are some rotten apples, it only stands to reason.
My only observative is that the "cop code" doesn't allow the good guys to rat out (for lack of a better word) the bad guys. Thus the bad guys have to do something really, really bad before they're removed.
Maybe it's that they don't really do anything bad enough to warrent removal or even something else, but I think I see this. Am I off base?
I have not seen anyone do anything what one would call really bad. When out on calls, I have seen officers who were perhaps not as sensitive to the vicitm as they should have been, but we handle that by talking to them in private away from others. Officers quite often Police themselves.
If I saw someone doing something unethical, thank God so far I haven't, I would report it. The Law must be respected and followed to the letter, even by those who enforce it.