Eh, it's one of the three major attacks on Amazon by a MacMillan author from a couple weeks ago, the other two are
Charlie Stross, and
John Scalzi. They're all suitably upset that their livelihood is impacted by the game of chicken is played by their publisher and their single largest retailer.
In some ways, I'm really surprised that these guys were so gung-ho in defending MacMillan. MacMaillan has never released ebook editions of Charlie Stross' series, and has been pricing their ebooks well above mass market paperback prices, so MacMillan's been sabotoging these authors with the millions of people who have ebook readers.