I have never had any encounters with shit on the streets of SF. Now granted, I haven't worked in the city in almost a decade, but this reputation it seems to have is nothing new.
I think if SF business owners weren't so fuckin' stingy about people using their restrooms then the people who can't afford to buy something at the grossly inflated SF prices just for the privilege of accessing a sanitary place to relieve themselves in privacy that the rest of us take for granted each day would be a lot less likely to shit or piss on the streets.
I remember waiting for the train after a night of particularly heavy drinking, and it was a 20+ minute wait for the next BART train, and I was already doing the pee dance on the platform. I knew I wasn't going to make it to the south bay before my bladder exploded. Station restrooms were already locked (even though trains were still running), so I went out to Market street and entered a nearby McDonalds. Asked to use their restroom, said I would buy something from their menu if necessary. Nope, they refused. I wasn't about to pee my pants, so you know what I did? I went and I pissed on the street right in front of their front doors. Problem solved.
If you leave people no possible way to do something "correctly", don't be surprised if they start doing it incorrectly on purpose.
