I suppose Chris Mooney has a bit of a point when he argues that his, um, "audience" is offside when they purport to a review a book which they can't possibly have read in the sense that it isn't published yet and, strictly speaking, hasn't even been written.
But I wonder if he is forgetting that uninformed commentary is hardly a monopoly of the right. The faculty lounges of world would be echo chambers if people had to demonstrate before discussing a book that they actually knew whereof they spoke. "No, I haven't read it but I'm perfectly prepared to discuss it" is probably not an Onion joke; more likely just a slip of the tongue. "You never asked a professor whether he has read a certain book," my friend Richard liked to say; "you ask him whether he has reread it lately."
Doubters may wish to pursue this inquiry may want to take note of Pierre Bayard's How to Talk About Books You Haven't Read (which, needless to say, I haven't)--still hangin' in there on Amazon at #565,433. Ever alert to the joys of cross-marketing, Amazon discounts it in company with Graduate Study for the Twenty-First Century: How to Build an Academic Career in the Humanities.