Unlike some others, I do blame Amazon for this. Amazon knows what the average person thinks the word "buy" (instead of rent) means, and then acts distinctly counter to that understanding. It's a bad-faith action.
I think it's ridiculous but the 'rent' vs 'buy' discussion is pure semantics.
You wouldn't say that you are "buying a revokable license to live in an apartment" when you sign a lease. You would say that you are renting. Why does it suddenly become buying if it's a digital good?
If you say 'buy a sofa now, free shipping!' and later claim that I got a revocable, time-limited licence to use that sofa, then in consumer protection laws that is perfect legal grounds to either say 'screw you, I bought it and your fine print is null and void', or request all my money back. It should be the same for digital content - permanent and with ability to transfer/resale, just as for books.
All truth in advertising laws are about 'pure semantics' if that's how you choose to refer to those kinds of distinctions. That doesn't make truth in advertising any less important.