Their aim is not justice, but pacification. Their purpose is only to maintain the minimum living standards necessary to prevent unrest and to keep the population functioning as workers and consumers. The state does not even pretend that social programs are about justice, because that would grant citizens the right to be free of economic deprivation. What I've tried to show is that the liberal state and its conception of justice are by their very nature hostile to social justice, to the idea that the law should enable people to live fully productive and dignified lives. Social justice turns out to be a kind of injustice.
Liberalism rests on a fundamental dichotomy between public justice and private morality.
On the one hand, there is justice and the law, the only scene of collective action, the only domain in which individuals are required to attend to the public good. Since this requirement is enforced by state violence, we naturally wish to keep it as narrow as possible. We don't want the crude methods of the state governing our relations with each other any more than is necessary. That leaves every other aspect of life in the realm of private morality where individuals are bound only by their own consciences and by whatever shreds of community norms they may be tied to. If I don't happen to feel a moral pull towards social responsibility, I am free to ignore it.