> Do people ever go to poor areas to enjoy themselves?
Absolutely! There are many poor areas in London (Whitechapel, Brixton or Dalston, for example) but the idea that you would have to avoid them is crazy. In fact there are great reasons to visit them - the best Indian or Pakistani food in the city is in Whitechapel, the music scene in Brixton is amazing, there are great clubs in Dalston if you don't mind the hipsters.
How has SF let things get so bad that there is a major area of the city that people are told to actively avoid because of all the homeless people?