Anyway, the parent's point seems to be that individualism is a strategy that is optimal for a single person, but suboptimal for society. The reason is that what activity maximizes your financial return does not generally maximize the return for society as a whole. Individualism is therefore not optimal. A specific example would be a world that had no crime and therefore no need for security, law enforcement etc. Obviously a lot more efficient than a world with crime. However, since stealing would be free of consequence, individualism dictates that you should steal in this hypothetical world. Everything may not be a prisoner's dilemma, but most is. I don't see how that's nitpicking.