By what principle does Swift arrange his list of advantages in A Modest Proposal?

Swift arranges the list of advantages of killing and eating the babies of the poor on the basis of utilitarianism. It is important, however, to note that while Swift wrote the essay, it does not express his point of view. It is the point of view of a clueless person who is so fixated on economics and utilitarianism that he has lost his moral compass; Swift wants us to be horrified by this person's ideas.
Since the narrator is chiefly concerned with economics—making the poor pay their own way—his first priority and first selling point is that his proposal can be described as,

[A] fair, cheap and easy method of making these children sound and useful members of the commonwealth.

He seems to lose sight of that fact that by making poor children sound and useful members of the commonwealth through killing them, he will also render them no longer members of the commonwealth.
He then moves onto his more "humanitarian" points, although they make no sense in the context of killing these babies: he argues that his scheme will prevent abortions and will give mothers an incentive not to murder their newborns. The mothers will instead wait until their babies are a year old to sell them for slaughter.
Swift wants us to see how inhumane and senseless it is to approach poverty and suffering only from an economic perspective without keeping in mind that those who suffer are also human beings.