Neither political nor religious discussion presents a problem. The problem develops when someone becomes obsessed, and campaigns relentlessly to promote their opinion. In other words, the problem is not with the subject; it's with a few members that as yet don't recognize, or care, that they are a problem.
Religious and political discussions may attract the problem (problem members), but subject isn't the problem.
Personally, I'd rather kick a few people off, rather than censor topics. It seems more fair to the group as a whole.