If you've been to the Tenderloin area recently, then yeah you would know "...[they] spit, urinate, taunt you, sell drugs, get rowdy..." is completely accurate. I recently observed a two days in a row a shop owner who had to wash the sidewalk outside his shop to clear off the human feces.

There is a homeless problem in SF, with as much money as the city spends on programs to help them I'm not sure why it's so much worse then other big cities, but it is.