The idea of justice and revenge, it seems to me, is inextricably linked; in such a way that it blinds us to the possibility that neither is necessary to our advancement, in terms of, understanding our fellow humans.
Sure there are those that seek to gain advantage over the rest of us because a genetic abnormality allows them to not feel and suffer, psychologically, the way the rest of us do (sociopaths and the like).
Might that advantage, through understanding, be mitigated and countered; that maybe leads to a more enlightened future?
Just a thought.