Slavic accent here. People definitely make jokes and I will probably never get used to social smiling. People generally assume I don't like them and/or that I'm mean. Easy to get around with conscious effort (used to practice the american teethy smile in the mirror).
If you're in tech, as an engineer or similar, none of that matters. If you want to be a starbucks barista I can imagine it being a problem even in SF. He did mention being in the menial side of the job market. That market is tough everywhere and why would they hire a foreigner that's culturally different when they can pick any number of other people knocking on their door?
Menial menial jobs (clenaing etc) mostly seem a market dominated by hispanics here in SF. Maybe he's the wrong kind of foreign to break into the market and build connections?