Justice is made up. Good and evil is made up. Those are all concepts that mean different things to different people from different time and culture. It means what it means.

When I say something is a right, it is meant as "in a proper society, it should be treated with the same importance we give to other rights".

Nothing has inherent meaning. Meaning is something we construct to not go insane from a meaningless universe because our brain has evolved to recognize patterns as a way to improve our chances of survival and has gotten too good at it for our own comfort.