> the sort of place that people feel unafraid to discuss controversial subjects?
> If the choice is between some outgroups feeling uncomfortable with civilly-expressed criticism of themselves
So this is the key tension. Outgroups get criticism of themselves every-bloody-where. As you noted, "We're discriminatory, hierarchical, social animals". One more place doesn't make the difference. What good moderation does is provide an opening for an outgroup to issue its own civilly-expressed criticism, with a chance of being listened to instead of reflexively ridiculed and dismissed.