Bill and Claude both threatened members here with physical violence. Steven did not, he should be allowed back.

I guess that's one interpretation.

In fairness, Bill challenged somebody to a sword-fighting duel. If you google "sword fighting duel" it appears that a duel is "a consensual fight between two people, with matched, usually deadly weapons in accordance with rules explicitly or implicitly agreed upon, over a point of honor, usually accompanied by a trusted representative (who might themselves fight), often in contravention of the law." The "consensual" nature of the dual is key IMHO. No consent = no duel.

In addition, I can find no published record of an injury suffered in a sword fighting duel in the US in recent decades. It doesn't happen any more.

Perhaps it was frightening to the target, but this was not a threat of sword attack. It was an invitation to an archaic consensual battle over a point of honor. He might equally have challenged his target to a Joust. ;-) IMHO it was an eccentric gesture, not a realistic threat. I accept that the recipient of the invitation was alarmed, but perhaps the dust has settled and things look different in hindsight- especially when we're asked to reconsider our thoughts about JVP in hindsight.