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...

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_...

And Europe too.

The below article seems to indicate and average of around 700k in the EU.

https://www.greaterchange.co.uk/post/does-europe-have-a-home...

>they treat everyone who enters like a potential criminal. They check your bags for weapons and run metal detector wands over you. Basically the worst library experience I've ever had

I don't believe there are many other parts of the world where this happens.