Social Justice is a grouping of words meant to sound like a Law. Justice is the application of Laws, whereas, Social is meant to apply to a collective or group, now called identity politics. Identity Politics is a political voting grouping tool, used to speak to a single group. Group identity politics is used by politicians, so they don't have to speak to individuals anymore.
The Indoctrination begins at an early age in our Public School system, which teaches kids there are no losers, only winners and everyone gets a badge. That is not how real life works. This has been reinforced with group politics, which herds children into identifiable causes. YOU parents ... you have zero say what gets pushed into your children's heads.
Long gone from our public education systems are teaching individual skills, promoting excellence, supporting unique skills, replaced by collectivism and Marxist ideology. In my own daughter's grade 12 English class, which is supposed to be about higher writing skills, the course content was totally on First Nation's genocide and had nothing to do with writing skills.
Jordan Peterson has some excellent videos on the subject.
If you really want to go on a deep dive about how we got here, I recommend searching the late John Taylor Gatto archives.