Ah, makes sense. I personally have never been to SF. I have this idealized vision of what it's like just from knowing that all the major tech firms are there but, I'm sure that vision is not entirely accurate.
So while the city does have a ritzy tech feel in the right parts, it is disconcerting to know that amidst so much concentrated wealth there are a lot more homeless people than you would expect. Really, a lot.
Unfortunately it's not as if these are all down-on-their-luck folks in between attempts at The American Dream. A lot of homeless people - in SF and in general - have mental illnesses and addiction problems and they do need help.