There is no excuse for a city with the per-capita wealth of San Francisco to suck as bad as it does, and "overzealous law enforcement" is not even on the list of problems the place actually has.
When a basic level of order is not being maintained, hand-wringing about a hypothetical police state falls flat with members of the public, some of whom are thinking fuck it, moving to Singapore sounds nice right about now.
There used to be an easy solution to this: vote for change. The problem, in my opinion, is that San Francisco has passed the political event horizon of single party rule. There is a monopoly government with no hope for competition and a huge welfare state that keeps the machine moving along. This won’t stop until they run out of other people’s money or Roombas are sophisticated enough to clean up streets. Of course, they’ll ban those too.