FWIW, if we are going to go down that road, it would be worth noting that there are various kinds of rudeness that can occur on IETF mailing lists. To my mind, the most harmful of these is not outright rudeness. Outright rudeness is to be avoided, certainly.
But the most rude behavior that ever occurs on IETF mailing lists is not listening. Not trying to understand what the person who is speaking to you has said. Not trying to figure out if what they said meaningfully contradicts your own position, and not making a sincere effort to determine if they might be correct in contradicting your position. We have seen some incredible rudeness of this type in the recent spfbis discussion, with various supposedly smart people in our community utterly ignoring what their opponents are saying, and simply re-asserting their own position in a variety of ways. I would expect the sergeant-at-arms to be reining in that sort of rudeness before reining in the sort of supposed overt rudeness that we are discussing here. The endless litany of repeats of already-addressed discussion points raised on the spfbis mailing list has been incredibly harmful to discourse on the ietf mailing list. This exchange between l.wood and Abdussalam Baryun pales in comparison. Furthermore, I would also point out that criticism of someone's behavior is not rudeness, if that criticism is accurate. I don't think the IETF should be a context in which people ought to feel safe in behaving badly, as long as they behave badly in ways that are subtle enough not to be considered impolite. Nor should it be a context in which failure to behave according to some culturally-relative standard of politeness in itself invalidates an otherwise valid statement.
