You're six years late, bro. It's pretty obvious that WoW is a simplistic MMO, but it's decent, I don't see why people bash it. I don't play it that often, but when I do, I enjoy the experience.
I want to know the answer to this if you find it tell me! My guess is that they either shit themselves when they see it is p2p or they get upset that the game they play which is most likely a f2p(with cash shop) is not as popular as WoW.