My argument is: (1) Feminism and race realism are interesting for the same reasons politics are interesting and (2) they aren't especially high value. If this argument is valid, then for the same reasons LW has an informal ban on politics discussion, it might make sense to have an informal ban on feminism and race realism discussion.

You don't address either of my points. Instead you make a slippery slope argument, saying that if there's an informal ban on feminism/race realism then maybe we will start making informal bans on all of social science. I don't find this slippery slope argument especially persuasive (such arguments are widely considered fallacious). I trust the Less Wrong community to evaluate the heat-to-light ratio of different topics and determine which should have informal bans and which shouldn't.

"some people will want to prevent or bias discussions of it for political reasons" - to clarify, I'm in favor of informal bans against making arguments for any side on highly interesting but fairly useless topics. Also, it seems like for some of these topics, "people getting their feelings hurt" is also a consideration and this seems like a legitimate cost to be weighed when determining whether discussing a given topic is worthwhile.