Seriously doesn't the pm function work better for all these board debates when it involves thread deletion. In the past several have been deleted from the forum after nasty open debates often with you. Why not pm back and forth and if necessary delete individuals without the debate on a thread. I suppose you tried all thoses avenues and I'm not privy to them so I'm only guessing what you have or have not tried.
Shotgun,
You're are spot-on there, mate. PM's are always the best way to handle these sort of disputes, probably because no-one is trying to win in front of an audience. Occasionally a mod will get a PM from a poster where he/she has not been able to make headway with someone else, (maybe even Simon, gasp!) this usually happens when there is a basic personality clash that can't be overcome.
Most of these things come down to using basic common sense IMHO. Mind you, I'm no angel either, having managed to get myself deleted from a couple of boards in the last few years.
What the hell, nobody's perfect, most things are retrievable. Providing nothing has been said that is too wounding, the admin here forgive and forget pretty quickly.
Englishman.