A part of the issue, allegedly, is that the Taliban cut Europe’s heroin supplies when it burnt the poppy fields, and addicts have turned to harder drugs. You certainly see a lot more broken people around, even if they don’t seem dangerous.
Sure, it’s a tad dicey in comparison to other streets in Frankfurt but it’s in no way comparable to what I’ve experienced in SF.
From my experience (I visit multiple times a year as my dad lives there) the homeless people and drug addicts in Frankfurt largely keep to themselves and just sit outside the subway together, albeit taking drugs.
I’ll never forget the fact that the lady in the Thai restaurant I visited literally locked the door and you had to knock in order to enter. Craziest thing I’ve ever seen. I feel safer wandering the streets of Delhi and Meerut in the early hours than SF at noon.