That is a good first order analysis, but I have witnessed HN darlings get away with far, far worse ad-hominem vulgarity with nary a peep from the moderators. This is most definitely about thoughtcrimes, and not manners.

For history's sake, let's link the original post which dang replied to and subsequently killed. There was zero rule breaking in that one, just thoughtcrimes:

https://news.ycombinator.com/item?id=11221055

As a scientist, I find human behavior fascinating. Particularly when people say one thing, and do another. My argument has always been as follows:

If HN is about entrepreneurship and technological progress, why do they ruthlessly suppress established scientific consensus?

And here's my hypothesis: because it does not fit the current political zeitgeist.