A lot of the flagged posts look completely fine, to me. Basically the entire discussion is greyed out, which suggests a pretty intense unwillingness to talk about the subject on principles alone.

I think by playing the brinksmanship card of "there can be no level-headed discussion" you inadvertently discount a lot of perfectly coherent and important digression, on both sides. If every HN thread resorted to this logic, nobody would want to use the site.