Not so political threads! Everybody is on equal footing in them. There's no "people with expertise relating their experience" and "people asking questions" and the rest of us reading with interest. Rather, everyone's broadcasting.
That's not inherently bad, I don't think; there are lots of other kinds of threads that are like that and they seem to be fine (for the most part) for HN's culture.
But politics is a particularly toxic combination of broad-spectrum and polarizing. There are never voices of reason or experience, the most active participants are often on a hair trigger, and participation is amplified because everyone's got an opinion.
Damn there goes our shot to hear what serious crypto people are really saying about Google TPUs.
:P
I strongly believe this, and I think the evidence is the content of threads where the mods gave people a chance. The volume, in both senses of the word, becomes extreme, with hundreds of angry nested comments.