You guys forget, WoW is multiplayer RPG, you don't just play for yourself. With that there is a definition out there for roleplaying games that predates computers, but it does play a role in WoW when interacting with other players (which makes WoW very different from singleplayer RPGs)
Does it really matter what people do in a game, isn't the genre definition about what you can do in a game? When you play Skyrim, do you go straight with the main quest, smack alduin in the face and be done with the game?