You're probably experiencing the problem I wrote about here: https://news.ycombinator.com/item?id=23308098. The fact that HN is a non-siloed site causes people to run into things here that they don't run into elsewhere, and it creates a shock reaction.
I bet you're particularly running into the international aspect, which is so much more influential on these perceptions than anybody realizes: https://news.ycombinator.com/item?id=23438403. The way people approach this topic in other countries is not at all the way Americans approach it. In particular, arguments that would make Americans wince (or "head desk", as you put it) are obliviously unobjectionable to users in other places, and those users have zero idea about the conventions they're breaking in an American context, or how inflammatory they are. It pains me to see these misunderstandings, but what can we do. "Excuse me, but the person you're disagreeing with is actually posting from $country, to judge by their IP"? Out of the question.