I don't think her statement, that she uses Amazon data to find other books her readers enjoy, is an admission of immoral conduct. She said a quarter of the books she recommends are from information she gained from Amazon. I believe she's referring to how she discovered them and not the reason she recommends them. Of course I am giving her the benefit of the doubt because the quality of the content on her site is generally high.
She serves her niche of intellectuals fairly well and I think spamming with lower quality content for the sake of making money would be noticed quickly by them. The donations on top of the affiliate links seems a bit much, but I think people might still donate and or purchase in order to show support for her work.