Came here expecting to see the usual nonsense "b-but computers are exactly like people and deserve the same rights!" comment, was not disappointed.
No one is asserting that computers themselves should have rights. But their users certainly do. If it is legal for me, a human person, to do something inside my own brain, why would it not also be legal for me to do a rough approximation of the same thing inside my computer?
they consented by virtue of publishing the work. If a human eye can read it, then consent has been given.
and there you've just put your own words into my post. Nowhere did the idea of selling comes into this (nor distribution of any kind).
If you publish, you implicitly allow people to purchase and read your book. The information and ideas learnt off that book is not subject to copyright.