I think you might be prejudiced here. Homelessness is a huge problem in other parts of the world too, especially Africa and parts of Asia.

https://en.m.wikipedia.org/wiki/List_of_sovereign_states_by_...

Let's split the distance. Every big city has some homeless, but no western European city has such problems with homeless people and guns to the extend to be a problem that requires screening visitors to a library, or having metal detectors, and drug and gun checks in public buildings...