Mmmh, he probably refers to things like developing Farmville. It is unclear why this solves any problems and not just wastes the time of users. But to be fair, if people wouldn't play Farmville doesn't mean they wouldn't find another way to waste their time :-)
That strikes me as one of those perfectly logical justifications for contributing to a problem: "Well, if we didn't produce cigarettes, someone else would anyway." It's also a red herring; it doesn't matter if someone else would or not, all that matters is whether or not we did the deed.
Well, you are right here, but that's essentially the point I try to address. Everyone of us has to decide on his own if he wants to work on something, which has no positive effect on overall society.