You really have no external problems with neighbors? People leaving trash outside the dumpster? All the other externalities of life near other people?
Where is this wonderful neighborhood? :)
> pick through the piles of trash and shit every time I leave my home
There are piles of trash and shit? Wow. Why don't you use your freedom and move?
> massive negative externalities they are causing are a result of them being homeless.
Words like "piles" and "massive" don't increase the evidence or reason; they aren't an argument.
Your argument is that you can't think of a solution, so you'll just abuse these people. Then your preferences are creating a massive externality. The people without homes aren't causing you to be arrested.