I notice you didn't include Alt-right in there which at the moment seem to be political ideology on a big rise and in my personal opinion, I think it's generally less radical than communism.
Consider though that one thing the alt-right will never accept is that racial diversity in the workplace is a net positive in itself. Whether it's true or false, it's just apart of the parcel.
Now how would someone like that feel comfortable in a workplace that tells you that being against racial diversity is racist? You don't even have to bring up your opinions, it's beamed to you on a regular basis through meetings, announcements and slack conversations.
I personally had a similar experience recently at my job in Australia in relation to the vote on gay marriage. Even though I am myself gay and have a boyfriend, I was in favour of a plebiscite.
This was in complete opposition to rest of the company, who went so far as to joint write a letter with other companies demanding the government not allow a plebiscite and to instead just pass gay marriage without a public vote.
There was alot of implication around that anyone who disagreed wanted the vote for a chance to vote no and more importantly, to allow for an advertising campaign against gays to intimidate the community as a whole.
People made the claim around myself that obvious the reason people want the plebecide is because they are homophobic racist rednecks.
I don't know maybe i'm just rambling at this point but It's just not nice to work in an environment where you have to listen to people trash your character based on your beliefs and you can't say anything otherwise your "discussing politics" and "rocking the boat".