It absolves them of responsibility for the problem and makes them feel like they are exempt from being at risk of homelessness. Since they aren't currently homeless themselves, this is proof in their minds that they aren't guilty enough to ever be homeless.

It's a convenient means to opt out of addressing social ills while simultaneously not feeling like that choice might come back to bite them in the butt someday.

More succinctly: "It is your fault for being a bad person. Society didn't do this to you. Not my problem."