Authors, Writers, Publishers, and Book Readers
I completely disagree with that. If I told you the true identity of Archer in Fate/Stay Night, you would have me banished from the internet and from all literature circles because the reveal of it is a major plot point and it really ruins the suspense of it.
Then again, you get stories like Body Rides by Richard Laymond where the plot is actually nothing special. I can tell you everyone that dies and only one of them had any major relevance to advancing the plot. It's still a fantastic read and was one of the first (maybe -the- first) full length book I read.
Still, I completely disagree with it. Knowing what's going to happen before you get to it can really screw up your perceptions of a book.