As to your first point, I gather San Francisco very rarely has weather so inhospitable as to render living outdoors dangerous or even particularly unpleasant. As to your second, I forget who characterized man as "where the falling angel meets the rising ape", but it's an apt enough metaphor, and we fail to encourage the former at peril of encouraging the latter.
If weather was the main factor, we would expect the homeless to flock to San Diego -- or even any of the southern states -- and not San Francisco. So there's clearly something about SF other than the weather that attract a large number of homeless people.
I grew up in Mississippi, and, believe me, brother, you don't want to be living outside come August -- it's nothing at all like San Francisco weather [1]. As for the rest, see my second point; if you expect nothing good of a man, that is precisely what you'll get.
As to your first point, I gather San Francisco very rarely has weather so inhospitable as to render living outdoors dangerous or even particularly unpleasant. As to your second, I forget who characterized man as "where the falling angel meets the rising ape", but it's an apt enough metaphor, and we fail to encourage the former at peril of encouraging the latter.