The fact that is it takes police over 3 min to get to a crazy naked guy assaulting people is crazy.
Also,
manaI've been there (I work in the same city), and suffice to say that station (16th St. Mission, on BART) is PROBABLY the worst one, anywhere on the BART system. That immediate area is terrible, full of homeless people who definitely should be receiving help, and while there is some police around, more security is warranted there, in my opinion (cops in SF aren't that bad; BART police is especially relatively good about their jobs from my time riding it).
That said, the dude was probably way off his mind (PCP seems to be the suspected drug). Really weird.
Totally know what you mean, i live near SF, and went for dinner with my family in the Mission(the one plus side of that area), and when we were walking back i think we passed the station, and its just full of crazy homeless people screaming and yelling, and i was scared