rewarding the “ability” to entertain any argument “no matter how ‘politically incorrect’” (to break out of some jargon, “no matter how likely to hurt people”) results in a system that prizes people who have not been socially marginalized or who have been socially marginalized less than a given other person in the discussion

To paraphrase: Our community is exclusionary in the sense that its standards for what constitutes an information hazard (and thus a Forbidden Topic) are as stingy as possible, which means that it can't be guaranteed safe for people more vulnerable to psychological damage by ideas than the typical LessWrong crowd.

It's possible that this problem could be resolved with a more comprehensive "trigger warning" tagging system and a filtering system akin to tumblr savior. Then there could be a user preference with a list of checkboxes, e.g.

Hide comments and posts about

[ ] Race

[x] Gender

[ ] Sexual Violence

etc.

This could also double as protection for people who want to participate in LessWrong but have, for example, Posttraumatic Stress Disorder which could be triggered by some topics.