[ben_w]

Vengeance doesn’t bring back the dead.

The prisoner’s dilemma has the equilibrium of defect-defect.

If racists regularly shoot ethnic minorities, that means members of those minorities have good reason to shoot first in preemptive self-defence; there will inevitably be errors, and then the ethnic group the racists belong to will do the same, and suddenly you have a literal race war.

Likewise for any other distinction that people fight over besides race.