I live part time and work between Berlin and Dresden. The old generation Turks are not the problem. The newly imported Turks are a mess are are the second generation of shiftless jobless Turks. Wherever the gypsies go trouble follows. I could see why the police would just stay out of those neighborhoods. Keep them in there and leave them to their own devices.
You can argue that the U.S. has the same thing in places like Detroit. I think the German population will get fed up eventually. As usual, people will have to needlessly die for anything to change.