So it seems like everyone agrees with Pachter. The story sucks but the game is fun. But some of the responses here make it seem like there is disagreement on this point. His statement isn't meant to ask how can a game with this much success have such a crap story. He is just saying that for a game that was obviously going to make tons of money, why didn't they make the story better.
Even movies don't have to have good stories to make tons of money. Look at Avatar and Titanic.