Seems like to me the issue is the guy told your son to go a certain spec, when your son refused(it not being his main) i guess he couldnt do anything about...at that moment. And when an item dropped for your son, out of spite he cheated him. That simple, its the nature of most wow players, its a game you cant "hurt" people so every oppertunity that comes around that can replace or facilitate that need wow players jump on it.

Out of curiousity was the guy who ninjaed the item a paladin too? If so then theres your reason. He prolly wanted your son to go a different spec so he could monopolize the item.

but from what i read, i can pretty much tell you that guilds like that dont last. Guild ldrs are just the person who owns the guild, not the people. And most of the time the ldr is the most uninvolved person in the guild. Or from my guild experiences they have been. Unless they are too much of a bunch of wusses who cant get into other guilds, he'll burn people one to many times and the guild will fall apart.