This is just bizarre to to me. I moved here from the Midwest, which I found stifling. There's a far greater variety of social values and political ideologies (not to mention backgrounds and interests) here than pretty much any place I've lived. The main hostility I see is to intolerance, but that's hardly surprising given SF's long, welcoming history and the paradox of tolerance. [1]
If I were to worry about any sort of uniformity, it wouldn't be political, but in startup culture. 20 years of success has created some very well-greased rails into which most innovation has to fit: bright young founders, seed round followed quickly by A and B rounds. That can be fine as far as it goes, but it has become so orthodox that I think we're not a great place for doing anything other than a plausible Next Big Thing.