What is economics? Is it a philosophy of death? No, it is a philosophy of life. Economics only includes the “allocation” of resources in support of life. There is no economics of death. Death is not an economic good that can be distributed fairly. Economics involves rational allocation. Just as there would be no point to irrational allocation, neither would there be any point to a theory of unfair allocation. So, all economic theories implicitly describe an allocation process that is fair.
However, most professional scholars who have chosen to specialize in “economics,” pretending they know something, look for other ways to define or describe economics. They look for some other principle, but not fairness. So, the rule is to find some method for understanding economics allocation, and not fairness. What alternatives are available? It becomes the matter of what is left, to the “economics field.” The alternative, or the one alternative they decided to promote was that of self-interest. And in this way they achieved the goal: they found something outside of fairness.