

The funny thing about that story is that its not supposed to be some sort of moral quandary, the suffering child isn’t the point at all. And that’s not subtext, the author straight up speaks directly to the reader and says its not the point.
And yet its practically the only thing I’ve ever heard people mention about it.
The author speaks directly to the reader about this:
She laments her inability to make Omelas seem like a real place, to convince the reader that such a society could actually exist, and invites the reader to try in her stead:
Finally, after some more description she again directly speaks to the reader to ask them if Omelas seems real:
When the answer is “no” they add the detail of the suffering child, which is necessary for all good things that occur there. How exactly torturing a child results in the city’s scholars being smart or ensuring good harvest is not explained at all, and yet by some narrative alchemy the setting is transmuted from something meaningless into something interesting.
The non-subtextual point of the story is that we as a people cannot imagine even a fictional setting without injustice. The subtextual point of the story is that we cannot imagine a society without injustice, fictional or not. Just as the people of Omelas described in the last section convince themselves that the injustice of their society is necessary, inevitable, and futile to fight against, so to do we convince ourselves that the injustices of our society are the same way. And yet there is some hope offered in the titular ones who walk away:
The author admits that she herself cannot imagine “the kind of place they’re going to”, in other words the kind of society that is not based on exploitation but is not an impossible utopia like the Omelas described in the first section something that could exist in the real world (it seems the author failed to convince even herself). Nevertheless these people who are not her “seem to know where they are going”. This is an invitation to the reader to try to do what she couldn’t by herself: figure out how to structure such a society.
So, you can see what I mean when I say that its funny that this story that laments our inability to engage with anything but suffering and exploitation, is engaged with almost exclusively by talking about the mechanics and moral implications of the suffering that it uses as an example of this very tendency.