Authors get a cut per book sold even if the ultimate seller is selling it at a loss. Amazon was increasing book sales by lowering prices, therefore helping both authors and consumers, while screwing it's competitors in ebooks and the publishers.

Apple's approach increased prices to be able to take a larger slice themselves and give a larger slice to the publisher (per book), but higher prices mean decreased sales. That screws both the author and the consumer.

So I'm with Amazon on this one, they acted as a single player in a market where they were not a monopoly (though a significant player), and were commercially successful through aggressive but legal means. Apple and the publishers basically ganged together to form a cartel that would exclude everyone else to either join them or else leave the market.