I know that seems mean of the GM, but I'd much rather see them taking steps towards proventing it such as that as opposed to just sitting around doing nothing. I'm pretty sure SE has gotten countless complaints about gilsellers, so whatever the GMs can legally do, they do. It's unfortunate that you were accidentally targeted for it, but I really don't think said GM was at fault just for stepping in and trying to do his job concerning that issue. If anything, you should be glad they're even beginning to give a crap about it. Not much they can do at the moment.