Social justice is all about ego. It's about placing yourself on a pedestal and saying "no, that's now how you do it, that's not what you say, that's not the right thing to think, that is so problematic! you're disgusting!" People get their thrills from going on indignant and didactic tirades designed to make themselves look like they're more informed, more cultured, more sensitive than you. I rarely ever see it come from an honest place, it's usually just people jumping at any and every chance to correct and lecture someone else. They learn all these -ism buzzwords on tumblr and jump at every chance to show off their shiny new toys.
Also I just feel like if you care about social justice you're ugly, i never see hot people care about this stuff. It's usually overweight people with nose piercings, half shaved green hair, ear gauges, the list goes on and on. It's just the new wave of that whole "i hate my parents, no one understands me" sort of thing. I hope i'm not offending anyone, i'm just being candid!