I think the main thing is the denunciatory rhetoric. I don't care if you're right or wrong (someone is going to misinterpret that, but it means the same thing as I don't care if I agree with you or disagree—as I've argued elsewhere in this thread, it's not the moderator's job to moderate on that basis). I do care when you hammer hardened talking points indignantly, because those qualities destroy the quality that we want here, quite apart from the content. It's a medium-is-the-message thing, if you like.
Actually, it's even less than that—I mostly just care that you don't primarily do that on the site. A certain amount is tolerable, more than that is not ok, and that word 'primarily' is how we test for that (https://hn.algolia.com/?sort=byDate&dateRange=all&type=comme...). It's not perfect but has proven to work well enough.