Well, some people like the law of the Jungle. They figure “it’s good enough for nature, it should be fine for humans”. The thing is though that nature is dumb and brutal and horribly inefficient…. “red in tooth and claw”. It’s why agriculture works better than hunter gatherer methods. It’s why culture, the reuse of what we learn, works better than instinct. It is why a balance of cooperation and competition can work far better than the raw limitless cut throat competition driven by Darwinian principles. It is why economics based on investment works better than hoarding. It’s why ruthlessness is not the best strategy for a civilization or the Roman Empire would still exist. It’s just that some people follow their tribal instincts and when they get in the driver’s seat of society they want society to revert to what they recognize and where their strategies work best. It’s not good for civilization.