The mysticism of "social justice"

If someone told you that country A had more “social justice” than country B, and you had all the statistics in the world available to you, how would you go about determining whether country A or country B had more “social justice”? In short, what does the phrase mean in practice — if it has any concrete meaning?…

The baby born into dire poverty might belong to a family in Bangladesh, and the one born to extravagant luxury might belong to a family in America. Whose fault is this disparity or injustice? Is there some specific society that caused this? Or is it just one of those things in the world that we wish was very different?

If it is an injustice, it is unjust from some cosmic perspective — an unjust fate, rather than necessarily an unjust policy, institution, or society.