Note that the link to the book contains the blog owner's Amazon affiliate referral code, so even if you disagree and click through to Amazon and buy something, he gets a cut. I'd love to see the economic benefit of this post to the author (along with the number of orders of the book the post actually induced).
This is not a moral judgment of linking to products you disavow, just intellectual curiosity about the results of such a counterintuitive marketing approach compared to affirmative recommendations of other popular books.