I'm neither istoriean nor expert on acient warfare. My quote was intended to substantiate the claim

Our kind might not be able to cooperate, but the Spartans certainly could. The Spartans were masters of hoplite phalanx warfare where often every individual would have been better off running away but collectively everyone was better off if none ran away than if all did.

My given quote indeed doesn't distinguish between Spartans and Athens... but that isn't needed as it appears that all hellenes were able to much better cooperate than their enemies. And from my reading of Anabasis this is substantiated. And my given quote is no bad one at that.