Take the Cataclysm expansion. Sure, Deathwing broke most of that stuff. But after our major battle with him, the results of his rampage remained. Mists of Pandaria is even worse - the destruction of the Jade Forest and the Vale of Eternal Blossoms can be laid directly at our feet, really - we're the ones who brought the Horde and Alliance to Pandaria and fought to get them a foothold. Now we're heading to Draenor, and we're leaving Pandaria in a shambles - he might be a massive jerk who fails to grasp the bigger picture, but Taran Zhu is right about one thing. It was us outsiders that destroyed his paradise.
On the other hand, if not for us, Deathwing would have destroyed Azeroth entirely and Pandaria would still be ultimately ruled by the sha, so to my eyes it's kind of balanced out. Can't save a planet without breaking some stuff.