There's no need to parse it anymore, I didn't get your comment initially.
for the same reason they can agree to cooperate in the repeated prisoner's dilemma.
I agree theoretically, but I doubt that utilitarianism can bring more value to egoistic agent than being egoistic without regard to other humans' happiness.
I agree in the short term, but many of my long term goals (e.g. not dying) require lots of cooperation.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.