The penultimate paragraph compounds my confusion: > For Mr. Hollock, the “Born to Lose” author, the issue is readers, not dollars. His award-winning book, published by Kent State University Press, had a steep list price of $35 to begin with. In the author’s view, Amazon is simply compounding the trouble by raising its price to more than $30 from $23. Why is the author complaining about Amazon, when the list price is…
For mostly historical reasons, wholesale price has become quasi-fixed at 50% of list. So in this case what's happened is the publisher has chosen to sell the book for $17.50, and the way you do that is by setting an entirely notional "list price" at 2x the intended wholesale price. But the $35 is not a real price; the real price in the publisher-bookstore exchange is $17.50. It's then up to bookstores how much they want to mark the book up above $17.50. Here, Amazon is choosing to sell it for a 70% markup above wholesale, whereas previously they were selling it for a 30% markup.
(This is U.S.-specific; list prices mean different things in different countries. Also, I believe the 'standard' ratio of wholesale-to-list varies in some categories, e.g. it's different for textbooks.)