My retired uncle lives in Kreuzberg with his family since he was a teen. They quite like it and just never moved out.

It has a lot to do with what you can expect from your neighborhood. A nightclub opening up right next door in a silent neighborhood is a recipe for a disaster, but it is similar with people moving into regions with a famous nightlife expecting a normal place to live. I for example dont have much sympathy for people moving in next to Frankfurt central station and then start to complain about the drunks, punks, junkies and hookers. Its like moving in next to train tracks and complaining about the sound of the trains.