As a complement to your points - it's worth pointing out that "blunt" != "intentionally rude" / "personal/character attacks".
I've seen lots of people on HN who are straightforward, but don't verbally abuse others when correcting them (although they might get a bit terse) - complaining about them is very different than complaining about those who actually start attacking you personally when you disagree with them.
(I, personally, try to be a polite form of the former, but as most people who have extensively commented on the internet can tell you, it's a slippery slope)
I've seen lots of people on HN who are straightforward, but don't verbally abuse others when correcting them (although they might get a bit terse) - complaining about them is very different than complaining about those who actually start attacking you personally when you disagree with them.
(I, personally, try to be a polite form of the former, but as most people who have extensively commented on the internet can tell you, it's a slippery slope)