Of course Amazon doesn't support it-- they, like the C&Ding authors, subscribe to the kool-aid of "everyone that was lending these books would have been a sale".
Not only do they support it, they actually pay a higher royalty rate to authors who enable lending (making the book lendable is one of the requirements for the 70% royalty tier). If you make the book an Amazon exclusive, you even get paid something when the book is lent (at least for the period of exclusivity).
My only point was that Amazon does not support people who run these ebook lending sites, and I don't think there's much of a future in it.