Actually, I have a better answer for you. Remember when WPCentral was WMExperts and the forums were joined with TreoCentral?
When the forums were split apart, that is what caused this problem. I see that all of chief7 post were moved to WPCentral (formerly WMExperts) and the spammer amopolos is left behind (banned) at TreoCentral. That explains why amopolos was not in WPExperts.