Again with the crawling over, and the ever expanding list of undesirable types.
I've been to Giants games and Athletics home games, I didn't experience anything but a ton of people having a good time at either.
I was out at night photographing in both Oakland and SF during the Warriors street parties during game 5 of the NBA finals in 2015. (for the record Oakland handled it WAY better than SF, who brought out riot police in The Mission for absolutely no reason).
My favorite Banh Mi place is in the Tenderloin, I suspect it pulls in a different clientele to Davies Hall, and yet, I've never had a problem at all
The condition of Bart cars is...not that bad at all for a major metropolitan city, I've certainly seen much worse, and if you have to stand so someone without a home can get some sheltered, safe rest, then I don't really think that's much of a hardship, but then again I don't refer to those less fortunate than me as "losers", and with "a homeless" you missed the word "person".
Doggy Bag wise, I'm not sure I've ever done it, but I've bought people food, and sat and eaten together with them, they're people.
Most people are a couple of bad months away from being in the same kind of situation, that might not be something you can identify with, but don't dehumanize them.
Essentially, our different approaches mean that I don't spend my time in The City in some kind of disdain heavy fearful flap, and I seem to have a better time there.