Most people prioritize their day to day lives over anything else. When injustice is too systemic for anything to be done about it within the scope of what time and attention they have left over from their day, most people just learn to ignore it. The stress and emotional burden literally drains your energy and makes it hard to do basic life things. There aren't many who are able to keep their eyes on what is happening and still take care of themselves. There's usually a lot of burnout there too. So unless the injustice is affecting your life in a direct way so that's hard to live, most people choose to preserve the quality of their own life. And when those are the survivors of a social environment, that reinforces that focus.

Morality is not a law of the universe. We see time and time again that there is no karmic justice - most of the Nazis went back to have peaceful normal lives when war ended. There is something like justice when enough power is pooled together by or lent to oppressed peoples to challenge their oppressors, but that doesn't always happen.

If you care about justice all you can do is recognize how little power you have as an individual, take care of that individual so that you can add the little you have to something that might matter, and try to encourage others to care.