If a good cop has to risk (and usually does) getting fired because they took a stand against a bad cop then its a rotten system. There are cases were a good cop lost their job because they took a stand and prevented a bad cop from killing a black civilian.
You have unions which will basically stand up for any white cop no matter how wanton and egregious the murder was and, lets say that everything goes right and a cop is properly prosecuted, then the jury may have one dissenter who will give an officer a pass, as in the case of Walter Scott killing, there was a hung jury and if there was no federal intervention, that officer would not have had any consequences.
As it stands now your mindset is warped to how things are in reality. First of all you are indirectly affirming that cops are a racist kkk institution. You have white, not black or brown cops in mind. Lets take the Black cop who "accidentally" shot the white Australian woman, , are you going to be sticking up for cops there? Of course not you hypocrite. You don't really care about cops, you care about white race solider cops who like to shoot Black people. Lets call a spade a spade. There is no good white race soldier cop.