I haven't observed it so it's probably a Bay Area/California thing. I'm in the south east and while it's slightly more liberal than the norm for the area most the people are still very capitalist, moderate right wing, and usually traditional social norms.

So yeah if you live in a super liberal place people are going to have a liberal bias. I was born and raised in the south, it has a conservative bias, and I don't pretend that it's magically going to go away. I think if you're aware that your political positions are a far deviation from the norm for your area it's probably wise to not be loud about it. Especially if your position is somewhere along the lines of "My coworker shouldn't be here for reasons that are a protected class". They'll fire you just to CYA, independent of whether they agree with you or not.