if I quote it from memory without attribution, it is arguably stealng. Certainly in bad taste to pretend that was my idea. If I type it out from memory on my blog page without permission, it is 100% stealing.

These aren't novel situations. We have centuries of case studies, precedent, and cultural osmosis giving us legal and de facto means of what we feel and say is "stealing intellectual property".

That's not what's happening. Using your analogy, you're reading the book, remembering it, and then making N more books (maybe for commercial purposes) by using what you remembered to create something very similar in terms of style, prose, plot, and so on. As a result, the person who you learned from can't get a job writing anymore because their work has been commoditized. Also, they're feeling lost because the work they devoted their lives to is now awash in a sea of similar work.