Yeah, I've met people with views so different from mine that our professional relationship was at stake.

Once it was a woman who seriously thought white men needed to be excluded from things to make up for all the time they oppressed everyone else. It was like socially-acceptable maliciousness.

When you talk politics, you risk having people reveal extreme views that really accomplish nothing but put a wedge in an environment what's supposed to be collaborative.

I think this is a major point, because even when you deal with really strong sports rivalries, it seems to be mostly play acting like they hate each other's teams. Actual hurt feelings are pretty rare expect for anger at particular events in a game (for example, bad ref call). With politics, it hits something much deeper in people and gets people to be side tracked for far longer, as well as possibly causing reductions in mood that translate to worse productivity.