I've seen [alleged] homeless people post on here before. Do you really need more than an interest in tech (and an internet connection) to read/post here?
I've seen them too, and I see no reason to question them. I'm sure there's indeed homeless people on here. I also have very good reason to believe they're a small minority. Try sample 100 profiles, especially of frequent commenters (not in "Get hired" threads). It is by its nature and origin an incredibly SV-dominated group. You and me are outliers.