So called "Social Justice" is an invention of the Socialist Ideals of the Progressive Movement. In America we embrace Blind Justice for all, of which Victor Hugo's Les Miserables is a vile anathema.
Justice, in a tradition going back to Aristotle, means treating individuals in accordance with their deserts...Justice is a very different thing from mercy, and mercy may be at odds with justice...
It will be apparent by now that the demands of “social justice” are incompatible with those of individual justice; to the extent that the first demand is met, the second must be sacrificed. If the government takes money out of Peter’s wallet to put it in Paul’s, it may have achieved greater equality, but not greater justice. It is impossible for individuals to receive a just wage on a free market and then be forced to part with a portion of it, for then they receive less than a just wage.
The final irony is that the ideals of the champions of “social justice” are not even achieved when they are put fully into practice. Because people will not—and cannot—produce indefinitely without compensation, the final result of massive transfer payments is equality of zero—universal destitution. That, after all, is how the excesses of the late Roman welfare state gave way to the destitution of the Dark Ages.[11] It has happened many times in history, and it could happen again if the proponents of “social justice”—that is, enforced collectivism—push their demands so far as to cancel out the requirements of individual justice.
From "Justice versus Social Justice" — By John Hospers
Just because you appreciate that God intervened for one individual, the more basic premise of the epic work is that social oppression is meted out to the dumb masses from the top classes on down.
That's not a premise, that's a reality. It is part of nature that the powerful oppress the weak. It is God's counter that the powerful use their power on the part of the weak. Hugo took way too many words to make the point (IMO), but that is the point. Without God, there is no hope for justice.