It just takes posts from 10 miles around your location. If you are in a location with primarily homosexual population, I'd imagine you'd get mostly posts like you did.
I live near a university, so all I see is drinking, smoking, classes, roommate drama, and hookups.
SF doesn't have a "primarily" gay population. It might be higher than other cities on average, but it's by no means the majority and certainly not in the financial district.
My guess is here there's isn't much for office workers to be sharing with strangers -- it's kind of a weird premise unless there's some specific city wide event like a parade or a terrorist attack. Thus the next logical reason for (gay male) strangers to interact is to hookup.
I live near a university, so all I see is drinking, smoking, classes, roommate drama, and hookups.