On Friday I taught Le Guin's "The Ones Who Walk Away from Omelas" again. This is probably the piece I have taught the most in my career. Inevitably my students make the same objection: why are they walking away? Aren't they just quitting? Shouldn't they, as the title of Jemisin's story goes, stay and fight? As I then try to get my students to understand, the students are transforming the kinds of questions that Le Guin's story is asking of us. She wants us to wonder what we are willing to give up, how we are willing to change, what we are willing to remove of our lives, in order to no longer be complicit of the suffering of the child. Political change is not outside of the questions, but rather deeply connected to them. The story implies that for change to happen, people need to transform through the outside.
The same is true for Deleuze. As you point out, these are questions here of subjectivity and subjectification. Who are we? Who are we becoming? What do we want? What are all the ways we have learned to hate our bodies and desires? And what are all the ways we've learned to turn that hate on others as much as on ourselves? These questions are not ancillary to questions of the political, they are bound up with each other. Strangely, we need to turn to Deleuze's empiricism to understand the political questions of subjectivity here.
In the preface to the English edition of Dialogues, Deleuze starts by saying, "I have always felt that I am an empiricist, that is, a pluralist. But what does this equivalence between empiricism and pluralism mean? It derives from the two characteristics by which Whitehead deﬁned empiricism: the abstract does not explain, but must itself be explained; and the aim is not to rediscover the eternal or the universal, but to find the conditions under which something new is produced (creativeness)." This is a very strange claim at first, that empiricism is fundamentally about a commitment to pluralism. In my empiricism primer I tried to explain some of the connection of empiricism and pluralism, but what is key here is that for Deleuze, empiricism--that is, a focus on experience--provides what he calls in his book on Foucault a "thought of the outside." This is what I was trying to get at in my posts on "Belief in this World" and in this post on Jamesian pure experience. There needs to be something outside of interpretation (however fleeting, however absurd, however unthinkable) in order to undue the images of thought. For James this is pure experience, for Deleuze it is the chaos of the plane of immanence. For Deleuze, it is the outside that gives us someway to contest not just the answers that are produced in the present order, but to contest the very questions that we ask. (While there are plenty of reasons that it might be hard to include Ranciere with this discussion, there certainly is something that rhymes here. For Ranciere, the part that has no part disrupts the counting logic of post-political consensual order. The post-political consensual order, what Ranciere often just calls the police, is used to fights about how to recount society. That is, they are used to arguments about how to cut up the pie. But the part that has no part challenges the very logic of counting and pie cutting. And that is why it is so unhearable and unseeable, so unthinkable. This is why Ranciere tells us in Disagreement that "politics is not made up of power relationships; it is made up of relationships between worlds" (p. 42). )
Just as Deleuze's metaphysics depends upon a transcendental empiricism to provide an outside to the problems of doxa and stupidity, the issue of lines of flight, nomadism, becoming-molecular, etc. are ways thinking the outside of subjectivity. And that is why they are always paired with other political questions. The nomads come with war machines. The witch's flight calls forth a new people and a new earth. The line of flight is articulated with George Jackson's imperative that as one runs, one should be looking for a weapon (and again, from the essay "On Societies of Control," "There is no need to fear or hope, but only to look for new weapons"). So Deleuze does not bring up lines of flight, nomadism, etc. as some sort of quietism, but rather as an outside that can create new forms of politics. Just as his empiricism is his answers to how we have novelty and creativity in thought, the lines of flight are his answer to how we have novelty and creativity in politics and subjectivity.
Think of that Deleuzian movie: Mad Max: Fury Road. They flee down fury road, but eventually the War Rig is turned around, and the Outside comes back to destroy the realities of Immortan Joe and his brothers and sons.