7 Reasons San francisco has homelessness 
 Housing is sky rocketing compared to its neighboring areas -- Noe Valley, the Mission etc.
It is a transportation hub thus It is safe
Some of the best restaurants including Gialina, Chenery Park thus good scraps left
There is an 80 acre park with hiking trails, rock climbing, baseball diamond, tennis courts, basketball courts etc making good area for tenting
The community has lots of soup kitchen and free welfare