Living in SF, I agree there is a problem. In fact there are two.
1) There are the schizophrenics who need some help (but nobody knows exactly what or how).
2) And there is the unfortunate reality of downtown: - smells of piss - no public bathrooms (because they become campsites) - escalators break on public transportation often because people excrement on them - trashcans get dumped out so people can find cans for recycling - people walking across certain busy streets ignoring traffic - various campsites especially in soma
I don't think this has to be an either-or issue. Helping the homeless is not an opposite of keeping downtown clean. I seem to notice people giving up on the latter though because they assume that the only way to do so is to blame the former, which is a no-no.