We have traditions of bluntness and flaw-hunting (mostly from hackers, who correctly consider niceness noise when discussing bugs in X), so we ended up rather mean on average, and very tolerant of meanness.

I think there is a difference between choosing bluntness where niceness would tend to obscure the truth, and choosing between two forms of expression which are equally illuminating but not equally nice. I don't know about anyone else, but I'm using "a-hole" here to mean "One who routinely chooses the less nice variant in the latter situation."

(This is not a specific reference to you; your comment just happened to provide a good anchor for it.)