I printed this out just so I could cross out every line except for one. And now, with renewed mental confusion, I wrestle with my sins against humanity.

Ok then please explain why Socrates is better than margin notes for an assumed purpose, because that is not reasonable common knowledge.

If by that you meant to suggest that for formal study, some kind of self-review process combined with cold written practice/rehearsal sustained under interleaved spacing, then that is likely the gold standard for comprehension and memorization. But most people don't even know that, either.

But the main premise is we should not assume all book reading is for rigorous self study. Margin notes can be useful for other purposes than direct understanding/retention (I admittedly don't know the psychology evidence for it but many academics routinely write margin notes here and there on (poorly written/edited) papers for purposes of idea generation, scientific criticism, etc. Presumably the Edison example mentioned above would have been more like that.).

How dare you gatekeep how people interact with literary material? Who(M)ever purchases/inherits/ditigizes/burns a book has to deal with it, and that dealing with could include ignoring it like a grown up, using some whiteout, or if digitizing, using any of the myriad photo editing software available. Sure, maybe don't put your grocery list on a first edition of some rare Chaucer book, but Chicken Soup for the Teenager's Soul? Study guides? Infinte Jest?

A book with notes is a guarantee that the book didn't spend its life sitting on a bookshelf not being read. If people are reading it is a net positive for overall human knowledge.

Lastly, your usage of Socratic teachings is a hollow appeal to authority. Socrates is dead and a modest library in an elementary school would surely have brought him to tears had he known how far we've come as a species, much less the remainder of books currently available.