Social justice is used as an appeal by the communist agitators to win people over to their cause. Some times they address valid social problem that exist in a culture, such as the racial discrimination that exists within a culture. However, the solutions that they offer to the disenfranchised will not offer a real and lasting solution. Violence and bringing down the system through revolution usually results in an even more ruthless tyranny than the one the revolutionaries wanted to replace.
The real answer to injustice is actual justice defined by God in the Bible. God describes what justice in the Bible. He gives very clear instructions on how justice is to be derived and administered. True justice allowed for the development of Western Civilization since God's law allowed for a ordered and just society to develop based on Christian principles of justice.
Social justice advocates have perverted the meaning of real justice and turned it into a system in which people are defined by groups who get different forms of justice based on their identity. The appeal to social justice can be very enticing because it sounds compassionate. However, real justice can only be defined by our Creator who shows favor to no person in the court of law. Tragically many Christian leaders have fallen for this perverted appeal to justice and wind up supporting radical Marxist groups that promote violence as the solution to an injustice that only Christian reforms can deliver.