The selfish and amoral side of human nature and of the human population has an advantage: the advantage of lying over honesty, cheating over fairness, theft over toil, aggression over negotiation.
If these were paired genetic alleles, we’d have to admit that the selfish ones have the edge.
But bullying and rule-breaking is also, by its nature, a minority strategy, because to open an unfair advantage a baseline of fairness has to be the norm.
So cheating must keep waxing and waning — an unstable, unsustainable strategy, whether genetically or socially — because if everyone lies, cheats, steals, bullies, the strategy has no victims left: Its advantage is over innocent victims. So a critical mass of those has to be sustained, otherwise cheating implodes…
…unless there is a way to enslave the victims, as humans have done to nonhuman animals.