It's not clear that the presence of those people on the earth requires official work channels to be a political discussion free-for-all. I spend time on a fairly small number of discussion sites. Invariably, the ones with the highest signal-to-noise ratio are the ones which ban gratuitous political discussion (including this one [Off-Topic: Most stories about politics, or crime, or sports, unless they're evidence of some interesting new phenomenon. ]).

Political discussion (like religious discussion) tends to generate more heat than light and I don't begrudge a company wanting to focus official work channels on, well, work.