While I would agree to that in the way that people should not spend all their time into one thing... You call it "a game".
I would call it a "hobby". WoW can also be a "lifestyle". Yeah I would even go as far as calling it that.
When I started this game (then it was still a game to me), I quickly became obsessed over it. Then joined a raiding guild. If you are an active member of a raiding guild, it turns into a hobby really. Much like being on a football team or any other hobby where others depend on you being there.
As I was a very very active GM of a raiding guild, it became far more then a hobby. I set aside everything for my guild. I had a huge responsibility, which together ofcourse with proper players lead me to making one of the better guilds on the server. I worked harder at my guild then I worked at my job. So then it became a lifestyle basically. Because everything revolved around it.
Meanwhile I can also say that I was def. obsessed. I had a lot of personal issues that I tried to hide from ingame or tried to solve via the game. Took me 7 years (and 450 days played on ONE character) to realise that this wasn't healthy either. So I quit being a GM or raider. I recently quit totally but have been decently active for a few hours a week these last few years.