Alan,
It is your prerogative to moderate as you wish, it is a thankless job, and I can understanding your getting annoyed with Abd. I would in your position. But maybe you can lead by example here and resist calling names just because others do it, and also take prejudices from past behaviour out of the equation? It would certainly be virtuous if you did...
Anyway, i'm not suggesting you should do this - it is not my place - but it might help the tone here.
"When we don't like things, the only person we can change is ourselves..."