I've been on HN for over 10 years. I also spoke with you over email under my real name more than once and I have a very high opinion of how you handle things in moderator's capacity. Which is why I must say that I find these ban threats very surprising, misplaced and disconcerting.
> differing cultural standards
Well, that's exactly the problem, isn't it?
What passes for normal "civil" behavior in countries like States and Canada looks like a completely fake way to express sentiments in other parts of the world. If someone asks "how are you?", they, more often than not, actually want to know how you are, not soliciting the "I'm fine" response.
What I said in the comment you killed I would absolutely not hesitate to say in person. I did not want to point out that his statement was wrong. I had an issue with the fact that he was commenting on things he doesn't appear to understand well in the first place. This was a personal remark, but I'm not sure which format you expect it to be distilled in to be acceptable as "civil".
If we are to reverse the situation, i.e. if it was me who blurted out something equally majestic, I would expect and prefer to be told just that instead of a wishy-washy pretense polite way. To me, coming from one of them "different cultural standards", the latter is a strange and alien way to communicate with others... which brings us right back to your remark about being respectful. Sometimes I'd be blunt when responding to comments I find particularly inane, but I also expect others to be blunt to me if the situation warrants it. Being blunt is not the same as being disrespectful, leave alone "uncivil".
> Then we all can learn something, which is the intended use of the site.
I've always viewed HN as a place for discussion with people of similar interests. Some may indeed learn a thing or two here, just like on any other forum, but stating that it's the intended use of the site is really quite strange.