1) It is often misunderstood, as this article from Catholic Culture reports :
An excerpt:
“A Connecticut bishop has defended the concept of social justice against critics who “have been telling Catholics to eliminate the term ‘social justice’ from any organization that speaks on Catholic social justice or has this expression as part of its title.” Auxiliary Bishop Peter Rosazza of Hartford is likely referring to comments made earlier this year by radio and television host Glenn Beck, a Catholic who converted to Mormonism.”
2) It is also often misinterpreted by dissenting Catholics, but—understood correctly—is a principle steadfastly embedded within Catholic social teaching, as the Catechism teaches us, and is the second guiding principles of our apostolate, as noted on the Lampstand website.
“We will work for social justice in all that we do.
"1928 Society ensures social justice when it provides the conditions that allow associations or individuals to obtain what is their due, according to their nature and their vocation. Social justice is linked to the common good and the exercise of authority.
"1929 Social justice can be obtained only in respecting the transcendent dignity of man. The person represents the ultimate end of society, which is ordered to him:
"What is at stake is the dignity of the human person, whose defense and promotion have been entrusted to us by the Creator, and to whom the men and women at every moment of history are strictly and responsibly in debt.
"1930 Respect for the human person entails respect for the rights that flow from his dignity as a creature. These rights are prior to society and must be recognized by it. They are the basis of the moral legitimacy of every authority: by flouting them, or refusing to recognize them in its positive legislation, a society undermines its own moral legitimacy. If it does not respect them, authority can rely only on force or violence to obtain obedience from its subjects. It is the Church's role to remind men of good will of these rights and to distinguish them from unwarranted or false claims." (Catechism of the Catholic Church, #1928-1930)