NYPD doesn't really fit your narrative of the rogue police department where the racism is just a symptom. If you look at, for example salaries, it clear that the city has a pretty good handle on the police union. Stop and frisk is legal (so far), and an explicit policy of the city government. And its a policy that's largely supported by the upper classes that run the city. And the public has largely supported the increased police presence under Guilliani and Bloomberg.