Imagine 100% human are greedy - there will be hunger games & we get extinct in no time. Hence, don't we need some moral standard to survive in peace?
Pointing the bots to a higher "moral standard" will not work unless they are programmed to follow it. But you can't refactor humans, sadly
Take for example all the technological progress of the modern era. Little of that would be possible if we didn't have massive, stable, cooperative societies. Any rational, selfish agent should recognize this and not resort to hunger games. This is also the reason capitalism seems generally more productive than communism. Instead of trying to fight or rewrite human nature, its more productive align incentives such that we can harness it.