Political discussion is supposed to be banned because it's mainstream, like celebrity gossip, and mainstream discussion dilutes the intellectual quality and purpose of the community and only hastens the Eternal September effect.

If anything, the moderators have probably been too lenient about letting political content through. It's starting to become the HN equivalent of a junk buffet. Far too little of it passes the bar of "satisfying intellectual curiosity," and far too much appeals only to tribalism and emotion.