Why is it her right to teach him a lesson?
Like a lot of other people have stated here, MMOs are about building a being and watching it grow. She has gone and killed something that obviously meant a lot to him. That account was easily worth a few hundred dollars as well. How would you like someone destroying a few hundred dollars worth of your stuff?
Also, not all WoW players are like this. I play WoW casually, and I love my characters about as much as I would love a...
WoW is fun, very fun, but quite a few people like him take it waaaay to seriously. Its guys like this that give the rest of us bad reputations, and create the stereotype for WoW, hiding the real fun of the game. If you can resist the addiction side of WoW, it really is a great game.