If Hacker News and Reddit comments roughly approximate SV attitudes, SV would be very right-wing compared to mainstream Europe on the whole.
In any case, this sounds more like other people's distaste is slowly grinding Thiel down and he's just trying to rationalise it to himself with talk of echo chambers and whatnot. You'd think he'd have more sympathy for minorities who have had to put up with that from birth but he does come across as someone who is frustrated when others don't subscribe to his exceptionalist view of himself.
It's not SV, it's Coventry he doesn't like, and he'll be sent there wherever he goes.