I cant speak from experience but my thoughts would be it had to do with location, homeless resources, prison systems and more.
I can only speak for Germany, but here it is not easy to get your hands on a gun. You could get a very convincing bb gun but for that you would need money.
Most homeless people don't save up because they are focused on survival. Which is why they set priorities like water<food<warmth/shelter<clothes<other stuff.
In the US getting your hands on a gun is generally much, much easier than it is for people here.
The prison systems also differ.
Here we are focused a lot on rehabilitation and resocialisation, so it could make sense for someone to go to prison.
But most would only act disorderly/belligerent/drunk in order to get into holding cells or 'Ausnüchterungszelle' for a night or two during really cold nights because while it isnt meant to be comfortable it is much warmer than it would be outside in the winter for example.
Sorry I ended up rambling and might have gotten a bit disjointed