Yes, some police officers do abuse their powers. But, that number is actually quite few. You are more likely to encounter an errant office worker than an abusive police officer.
The problem here is that encountering an errant office worker isn't likely to result in legal troubles for me, but encountering an abusive officer often does. More to the point, the concept that very few police officers abuse their powers is ludicrous in my experince with many police officers. The vast majority of officers don't maliciously abuse their power or do stuff that's extreme or egregious, but I've never met an officer who hasn't done stuff like running criminal checks on their neighbors just because they can or skating a traffic violation by flashing their badge to the arresting officer.
If you have encountered an abusive cop, I would suspect you probably were in the wrong in the first place, no?
Part and parcel of the abusive officer's creed, this is. No, it's not necessary to be wrong to be mistreated by an abusive officer, because that's the definition of "abusive".