Urgh. You're quite right, of course.

I think, obviously, that there's a huge distinction between working for pay and donating one's organs in the way those Donors do, but... you're entirely right that joining the army is a pretty close cousin to what Donors are doing (especially when it's truly or implicitly mandatory, either legally, because of lack of other options, or simply through coercion), though joining an army entails, as you've said, a *risk* of death, rather than a certainty of it (obviously that risk is much closer to a certainty for child soldiers and other soldiers in poorly equipped armies, making your point that even more apt in those situations).

Also, I think that, for me at least, and I'd guess for other people out there, being required to go out and kill people might actually be worse than being required to donate my organs until it killed me. At least the Donors were able to see themselves as entirely noble, giving to others, and weren't forced to destroy anything or anyone other than themselves. I hadn't thought that far outside of the context of the story.

Thanks for your responses; they're really helping me think this through much better than I had initially.