Its not uncommon for a large portion of that group to carry weapons.
When you are surrounded by people on hard drugs, the people that sell them, criminals, etc, theres a good chance you dont trust the person standing next to you.
Add in being paranoid from all your previous life events, and theres your reason to have weapon x on you at all times.
The above event of the police officer disgusts me, and reminds me to be more cautious when i go to work.
We work in alot of the shelters, and its not uncommon to see questionable shit like weapons on roofs, ceiling places, etc
This is my favorite one, in a surrey shelter