You can burn you book, tear it up, use it for a placemat and eat off of it. It's your book. You can hand YOUR book to someone to do it for you. But you can't buy one already butchered unless the author ok's it.
So please explain to me the logic you see in that distinction. If I can hand a book to someone else to mess it up for me (presumably for a fee, or else this hypothetical of yours isn't even in the same league of what we are discussing), then why can't a person buy a book, mess it up, and then sell it to someone else?
Then most college bookstores are in violation of the law because they sell used books that have been so altered by the previous owners. And could you point me to a law that says I can't resell a mangled book? I know you think that is true, but where's the cite?