"Rationally"? You mentioned you had all sorts of nice experiences with homeless people and then one bad actor caused you to choose out of all of the attributes of this person, their lack of a home, to be the one for you to blanket-label all people like this as dangerous enough to place them outside of your treat-like-a-human-being sphere.

Nah, there is not a rational way to blanket label groups like this from a sample size of 1. That's your trauma talking.