To use the term already mentioned, he ruffled the feathers of a long time member way too much - in fact he was downright rude. This was not the first time that he had overstepped the responsibilities of a Mod but it was the final straw. He refused to accept the problem existed and then, as a parting shot after he had been demoted, he went through the forum permanently deleting vast swathes of posts which contained anything that he had contributed.
He shouldn't have been able to do this and it was an unfortunate mistake to have left him with this Mod ability. It caused a great deal of trouble to the forum and we eventually had to revert to a backup of some days earlier which lost all new posts since that backup but regained the ones he had deleted.
He will not be coming back.