Just pointing out what happens when you put good cop in quotes.
Most cops are not good cops by your definition and from my experience most are not good cops because they turn the other way and actively keep quite about bad cop activity. They see themselves as the good guys but employ bad guy behavior in the name of doing the right thing. Which makes them bad guys. Only a few go against the grain and report on bad cops, these are quite few and are actually newsworthy when they do so.