reading it after stealing it: gray area. producing & monetizing competing works devaluing the original is a problem

So is it a problem when humans produce and monetize competing works? My understanding is that there quite an industry in humans reading books and synthesizing their points. Cliff's Notes, for example.

I did some quick googling and most of cliffs notes guides are on public domain works so no problem there, they've also paid to license content, and also have been protected by fair use as parody

To Kill a Mockingbird, The Catcher in the Rye, Beloved, The Kite Runner, The Handmaid's Tale are all copyrighted works with a Cliff's Notes guide.