"Social Justice Class" is a euphemism for political indoctrination. 
"Social Justice" is just a code-word for political revenge, aimed at representatives of out-groups as characterized by the Left's Identity Politics of the moment.
Which is why they can rationalize the beating of a first-generation Polish-American on a subway platform by American "blacks" of mixed races, some of which have white-slave-owner blood. The victim of Polish ancestry never had anything to do with slavery in his life, save that his father was in Auschwitz. The black had nothing to do with being a slave, since his father was a second-generation whose family was from the Dominican Republic, and his white grandmother a French charwoman.
But somehow the agenda-driven, propagandist, Fake-Nooze Mediuh, sees the need to defend such SJW attacks, assaults, public hectoring and disrupting of others who are just living their lives.