What is the theory considered for Omelas?

In “The Ones Who Walk Away from Omelas,” Ursula K. Le Guin deploys a motif seen often in science fiction: the dystopian society that seems, on the surface, a utopia.
This utopia, however, is built on the suffering of a single child. The story is a rhetorical exercise, a thought experiment, asking us to consider suffering in our own society. In the introduction to her novel The Left Hand of Darkness, Le Guin defines science fiction as “descriptive” and not “predictive” thought experiment: “The purpose of a thought-experiment [is] to describe reality, the present world.” In this sense, Omelas is our world. Our world is built on suffering: one group is exploited so that another may prosper.
Defenders of this social order might say that the number of people suffering in the world has decreased; Le Guin asks us, can society be considered just if “only a few” people are suffering? What if it were only one person? What if it were a child? The story asks us to see our own society, whose shortcomings and brutal history we often overlook, through the lens of the fictional city of Omelas. How you choose to answer those questions after reading the story and reflecting on our own society would lead you to an interesting argumentative thesis statement for a paper on Le Guin’s story. You can use Le Guin's theory of science fiction as a thought experiment to guide you.
Taking a different approach, it may be useful to note that “Omelas” spelled backwards is “Salem,” which, of course, conjures images of the Salem Witch Trials. The so-called “Witches” put to death in Salem were scapegoats, and the child upon whose imprisonment the prosperity of Omelas depends is himself a scapegoat. The scapegoat has a long history in Jewish and Christian theology.

In theory, the city of Omelas is a perfect Utopian society. The perfection comes at a cost, which is the suffering of one child, a scapegoat, which makes the reader call in to question whether or not the happiness of the majority is worth the suffering of one. Omelas is only perfect in theory; this is demonstrated through both the title and the ending of the story. If Omelas is such an idyllic place to live and everyone is happy, than why do some people choose to walk away? Do these people who walk away feel guilt for the suffering of the child? If some can feel guilt than is the society perfect? Omelas is an idea rather than a real place. It is an allegory for our modern society and modern governments in many ways. In democracy, where majority rules, what happens to the disenfranchised minorities?