Because this is still a new, and somewhat controversial idea, and the article spent a lot of time considering the alternatives and explaining why their proposed

Because this is still a new, and somewhat controversial idea, and the article spent a lot of time considering the alternatives and explaining why their proposed idea seemed to fit the data best. Without it there would be no reason to take their idea as more credible. Now I dislike pointlessly long articles, and certainly this article could have used with an abstract to put forward the main thesis before delving into alternatives, but I don't think your criticism is entirely fair. It certainly didn't fit the pattern of the really long articles where the writer invariably talks about their childhood or some other barely relevant events before actually talking about the issue at hand.