Cloning people for harvesting organs doesn't really make that much sense: it'll take many years to grow the organs to the size needed to be useful as replacements.
We're already working on growing (or even 3D-printing) replacement organs without the human; that avoids ethical problems, but it also doesn't require the huge investment in time and resources needed to grow clones of yourself and raise them to adulthood. They'll probably have this technology ready for prime-time before they could have human cloning working plus have those clones grow to late adolescence.
That's my point. We don't need "the island"; when we've worked out the genetic issues with cloning, we'll already know how to just grow organs on-demand. The whole clone thing doesn't make that much sense when you look at it that way; it would cost a fortune to raise a human to adulthood just for organ harvesting, plus garner all kinds of ethical problems and controversy and protesters etc. No one's going to protest organ-growing or 3D-organ-printing except maybe a few religious nuts.
And with the clone, what happens when you harvest its heart (killing it), and now you need a lung? Or you harvest one thing, and then get injured and need that same part, but you didn't have multiple clones lined up? With organ-printing, you just make the organ you need when you need it.
We still don't have truly 100% working clones; we tried with a sheep a while ago and it wasn't 100% and died early. However, we're already experimenting with 3D-printing organs.
It would take extreme idiocy to think that this is morally sound. There is no defensible argument for treating a human clone as anything less than human.
That's not how cloning works. Clones aren't empty husks full of free organs ripe for the taking, any more than non-clones are. Even if you could create a clone without a brain, it's still hard to condone. If an anencephalic fetus miraculously grew to 24 years of age, would people post a "free organs" sign on him and lay him down on their lawn? Gonna have to say... probably not.
We're already working on growing (or even 3D-printing) replacement organs without the human; that avoids ethical problems, but it also doesn't require the huge investment in time and resources needed to grow clones of yourself and raise them to adulthood. They'll probably have this technology ready for prime-time before they could have human cloning working plus have those clones grow to late adolescence.