I guess, its my turn to answer this.
First, let me make clear that evil != bad for me. The game can obviously be much fun for the many people who play it, also possibly could be much fun for me if I played it (but I honestly don't know). Also, I don't know most of the people who play it, hence I'm neutral about them.
BUT this game is obviously quite addictive. And thats why its evil: it consumes peoples time and keeps them from doing useful things. That is my only argument. And yes, I see it that way for all mmorpgs, maybe even most computer games (but lets not turn into that direction as that may lead to the thesis that op2 is evil).