A recent exchange between Tim King of Sojourners and Jonathan Witt of the Acton Institute illustrates the problem with the concept of "Social Justice". Witt points out in his American Spectator article, that "social" is a modifier that is often used to obscure the essential meaning of a concept - in this case, justice. The Gospel is already a social message. It's not a private or solitary concept that must be modified to be properly understood or implemented. And justice is already a clear concept which, while it does often apply first to individuals, is only muddied and endlessly evolving in the hands of the religious left when modified as in the term, "social justice".
The concept of social justice has a history reaching back nearly two centuries in Catholic use, but it has been co-opted and morphed by the religious left into an ill-defined program of coercive wealth-transfer administered by the government. The problem is that these federal programs are often inefficiently administered. In addition, because money is fungible and not all equitably used, bad actors can enhance their position and power (this goes for international aid as well as individual recipients of welfare payments). Programs administered at a level far from the recipient can also destroy more efficient and effective local solutions - the opposite of distributism*. When this happens countries that had been exporters become net importers and big daddy government replaces real fathers as the source of income and protection (resulting in what has been called the feminization of poverty). This top/down model of charity/aid has trapped many a country and many a family in a "vicious cycle of paternalism and dependency" (Witt).
So, while social justice has legitimate roots, the way the term is used by the religious left emphasizes a top-down government-based approached rather than a local community and organization-based approach which includes churches and civic groups. The concept as used by the religious left most notably ignores or dismisses that most basic of human rights - the right to life. See Sojourners own position on abortion which refuses to take a stand against abortion and in support of the right to life.
For what is justice without life?
For more on distributism, see: American Chesterton Society