The comment was about heroin. Were you offered heroin?

Is cocaine and marijuana available from the government too? If not, what relevance is your comment?

Was this the first and only time you were waiting at a bus stop in Switzerland? If so, perhaps a notable story, if not then we'll need more information to conclude how bad this thug problem really is in Switzerland.

Langstrasse is as close to a red-light district as you'll find in Zurich.

It's gotten a lot better over the last couple of years, but stating that you were offered drugs there is like being offended that you walked past a casino in Vegas.

The problem is definitely with adultered products. Never accept anything from a random "thug".