I wish someone had said this to me 6 years ago. Maybe it’s obvious, maybe controversial (I’m actually not sure), but I figured it’s worth mentioning.
Math for social justice definitely is using mathematics to analyze social systems and real-world situations through a critical lens (i.e. racial patterns of home ownership or average pay rates).
Math for social justice also, definitely, is posing interesting problems (related or unrelated to real life) to students and encouraging/facilitating/coaching them to use their personal understanding and knowledge to puzzle through it. Or, posing rich situations and having students write/answer their own questions.