Having known nothing of this tale but rumors that it was striking coming in, I would have preferred that the introduction had been placed at the end. I entered instead forewarned, spoiled, because I could deduce it'd be some beautiful Le Guin version of The Lottery. Then again, this is less a story than a question or a parable, as the author herself says in the after-word. It certainly left me thinking (particularly, of the photograph of the vulture by the dying child, but also of third world country people producing luxury items for paltry food and roof).
I loved this quote:
"The trouble is that we have a bad habit, encouraged by pedants and sophisticates, of considering happiness as something rather stupid. Only pain is intellectual, only evil interesting. This is the treason of the artist: a refusal to admit the banality of evil and the terrible boredom of pain."
As for my thoughts on it (disjointed still)
Part of the beauty of the set up is that being contained, the possibility of denying the bargain and the way is clear. In practical terms, leaving does nothing for the child; it only assuages the personal sense of morals. Doing something for the child, taking the child from misery, condemns all others to it; morals wounded by the misery of one would not perpetrate same on many. Freeing the child would be the equivalent of a violent revolution by a minority. Each that leaves takes responsibility for their own choice. The hope is that at some point, nobody takes the bargain.