In the rest of Germany there are cities you can easily spend months in without encountering a police officer.
Weed is definitely widely tolerated. Many people are in favor of legalization not just among those that enjoy weed but also among people working in the justice system that recognize that prohibition isn't working. Legalization would make it easier to deal with addicts, make it easier to prevent children and teenagers getting weed, would make many parks nicer to visit and bring in taxes. I think that it's just a matter of time until public opinion shifts to the point that it will be legalized.
Nevertheless the time isn't there yet, the senator responsible for police is member of the CDU, conservative and in favor of prohibition and unfortunately, while it's mostly weed, it's not just weed and many people aren't too happy about the aggressive sales tactics.
Politicians meddling with the justice system, because of a (partly misguided) public outrage.
As a result, Mollath got off.
And our "justice" system suffers from massive, massive understaffing, just like the police. It's easy to "cut costs" there for politicians because there is no immediate negative effect, and by the time said effects hit, the politician responsible is not in office any more.