Have you seen any of the episodes?
It's fantasy and it's on cable, so they can pretty much get away with anything. Heck, if they can go after the all powerful dwarf-American lobby, nobody is safe.
Smarty-pants culture journalists create controversies about racism and sexism in fantasy worlds to attract an audience. I really doubt anybody is that serious about such complaints, especially since those "stereotypes" don't all run in one direction. But I could be wrong: Seitz and his colleagues could be that silly.