I don't know what the big deal is. If someone is doing something that makes them happy and doesn't actively hurt themselves or others, why is that wrong? I regularly play 8-12hrs a day playing or talking about computer games. And guess what? I'm a (lie) normal human being. I just happen to like playing video games a lot. Personally, I would prefer to be happy and girlfriendless than miserable.
I have been in total lockdown at points in time in my life. The most annoying thing I ever hear is "you're addicted". Well, I ask this imaginary person, are you addicted to television? You sit and watch it for over four hours a day, why don't you do something else? You watch the news and buy newspapers every day, you eat breakfast or catch the bus. Are you addicted? Or is it just your lifestyle choice?
Video games are recreation, as well as literature and social interaction (this is one of the more addictive components of MMOs). You can do a hundred times more by virtualising your intentions and swathing your own path virtually than you could if you were to try following a similar agenda in the Real World. I guess I am fortunate that I do have real-world achievements, education and reputation I need to maintain and I manage by keeping my gaming life and my real-life separate. If he likes gaming so much, maybe he could find employment in that.
Oh and I never played wow, but I do play another MMO that normal people (including wow fans) would think is completely insane.