Ok, maybe it's because I'm older (but not a boomer), but I don't think that's an awful work environment.
I use dinner party rules on social media and at the workplace. That means I avoid talking about politics, religion, etc. It's not because I'm afraid of being outed for my views or anything, it's because I look at work as work, and not a place to socialize or broadcast my views.
If so, that seems like the same dynamic, just with a different hegemony. It's a horrible pattern for a workplace regardless of which view is the orthodoxy.
That won't protect you. When your employer is actively signalling and funding support for particular groups or political positions, failure to join in is taken as a political action, and you might get attacked by co-workers for being anti-group or anti-position.
Maybe I'm lucky, in my 25+ years of working, I haven't had to deal with that level of unprofessional behaviour (but I've also generally avoided working with startups and "interactive" agencies for the past 10+ years).
FWIW, I see those chiding posts in my FB feed, and I don't put any stock in them. Most of the people in my feeds post them in lieu of being genuinely active, as though the act of posting is an act in itself. That's their right and choice, and it's my right and choice to ignore them.