It is bondage rape porn. Bondage rape porn that is for some reason celebrated as “woman’s porn”.
Chew on that for a bit.
Having read the wiki plot summary, the book is a woman's fantasy on many levels. A college senior who works at a hardware store hooks up with a handsome, 27-year-old billionaire entrepreneur, who dominates her, showers her with presents, and becomes totally obsessed with her.
Look at women's romance novels and note how many are about some wealthy/powerful man who falls for some ordinary woman. How many of them involve the woman being "ravished" by the dominant man who just cannot control himself in his desire for her.
This has been going on "under the radar" for a VERY long time.