Actually, the reason for that title was because of a point I decided to leave out, but may as well spell out here: "Deciding to talk about politics, even though this may cause you to lose some of your audience" and "Deciding to tell people they're wrong, even though this may cause you to lose some of your audience" are both tradeoffs, and it's odd that LessWrong community norms go so far in one direction on one tradeoff and so far in the other direction on the other tradeoff (at least with regards to certain subjects).

I have had experience as a moderator at a science forum, and I can tell you that almost all of our moderating involved either A) the politics subforum, or B) indirect religious arguments, especially concerning evolution (the religion subforum was banned before my time due to impossibly high need for moderation). The rest was mostly the better trolls and people getting frustrated when someone wouldn't change their mind on an obvious thing.

However, I must say I don't see how people can discuss rationality and how people fail at it without someone telling someone else that they're wrong. After all, the major aspect of rationality is distinguishing correct from incorrect.

Incidentally, I've been really impressed at the quality of comments and users on this site. Consider what this user has observed about LW before you complain about how politics is not allowed.