I'm continuously astonished by how many people don't see this as the problem it is.
It isn't just a SF problem unfortunately. While it hasn't gotten nearly that bad yet, it is getting to be a more pronounced problem in my city. The homeless shelter is in downtown. They turn people out at 7am. If you go before 830 or 9, you will find people sleeping in the postoffice foyers til they run them out, and piled up around the public library and along a wall behind it. Most of them are young white dudes and they are high as a kite when they are walking around so clearly this is a drug thing. A lot of business have had to lock their outdoor receptacles and spigots because they would all pile up around them grooming or charging their phones.