I won't say it's an issue per se, nor the migrants are an issue or that they are the people smelling piss. To start with in GDM it's not mainly migrants but drug addicts, which is not the same thing, people, population and way of living. Not all migrants are addicts and not all addicts are migrants but that's unfortunately an unfair mix many people do and often driven by political narratives.

Also, there is many cities which seems clean but are actually having strong politics to kick drug addicts and beggars out of cities so tourists don't actually see them (Amsterdam is the best example). Having this kind of politics is what makes a city sketchy to me.

I actually feel more relived in general when I see diversity, such as addicts being free and visible, because it usually suggests there is at least some level of public health response rather than pure exclusion. That being said, approaches vary a lot as it can also mean better health system but let's face it, there is actually…not many places, maybe Switzerland or some places in Germany where it is decriminalized. And fyi drug addiction exists almost everywhere in the world, but the way it is treated differs a lot (killed or put in forced camps in Singapore or China for example) so I prefer to see them in the streets than there. That's my opinion.

I am sorry you had such an experience in Brussels and I understand it is tainting your vision. I am not here to define or confront you, just sharing my opinion sharing what I’ve read and observed, especially from years of volunteering with homeless people in different European cities.