Again, when it comes to proper policing - solving violent crime - they absolutely are. When it comes to harrassing people at random, the police wildly overdo it (as in, they shouldn't do it at all). Whether it's the shakedown force that Ferguson operated, or the people who just run around hassling whoever they see like in Baltimore, the police in many of these areas have *never* established themselves as a force for justice, law, or order. Instead, they've operated as a street gang with the court system behind them, and thus are afforded the appropriate level of respect - or rather, the appropriate level of contempt.
And since the police are nearly useless in solving violent crimes, it means both that a person who attacks you will likely go free, and also that you'll likely go free if you retaliate. And that's why minor beefs over someone stealing someone's girl or whatever regularly devolve into gang wars.