Earlier quoted context omitted.
As a new Berliner who immigrated here I can answer some of those: - Berlin has a reputation for its artsy party scene and lax enforcement of drug laws. People come here in their 20s to let themselves loose. - German universities are good quality and free for all (excluding the Semesterpauschale, but for my American or British friends this 300€ is basically nothing in comparison - especially when you count in the publ…
You're not kidding about lax enforcement of drug laws. In Kreuzberg I'd often see people obviously offering to sell drugs to passers-by as police cars would drive down the road practically next to them. On the other hand the police does occasionally decide to make a show out of its enforcement. I think it's more appropriate to call it "selective" than lax, at least by German standards.
Try to do the same in places like Munich. The police can stop your taxi, search your pockets and bag, and if finding some illegal substances you lose your driver's license and need to go to the court. This will (hopefully) change for weed this year...