In game theory, cooperation is a dominant strategy and evolves consistently. Slave owners and other injustice committing humans often invoke "human nature" out of trying to cope with their knowledge that it is wrong but whatever trauma or other thing makes them do it anyway, to absolve themselves of agency.
(To be clear, not targeting you personally here, but targeting the rhetoric and fallacy)
Cooperation is an unstable strategy. If everyone else is cooperating and not punishing defectors much, defecting is vastly better for you.
If everyone else is defecting and you can cooperate with a few people, that's slightly better for you. Hence we have high-trust and low-trust societies, gatekeeping, etc.
Sure, and now compare polities which manage to keep defection to a minimum or structure the process of "defecting" to serve the polities purpose instead of being truly adversarial. Bruce Bueno de Mesquitas "the logic of political survival" and various works by daron acemogolu have the data on how much better these polities do.
If there's no pure play dominant strategy, you will always get a fraction of defectors willing to try their luck. But coopération still emerges, and the polities that manage to cooperate more still tend to survive and thrive more.
Many kinds of defecting aren't punished much. For example we don't refuse to buy things made with slave labor. Some people do, but they're an extreme minority. So being a slave owner is rewarding.
(To be clear, not targeting you personally here, but targeting the rhetoric and fallacy)