When one claims all entities act in their self-interest, one is ignoring massive evidence to the contrary, throughout human history. And by 'history' I don't mean white male patriarchy recent history but actual human history, everywhere, over tens of thousands of years.

The story (myth) of 'self-interest' as primary, when repeated as fact, becomes self-fulfilling, and that is part of our problem. Likewise saying humans are 'selfish' based on being born into a society that happens to glorify and promote hyper-individualism and hyper-selfishness. Ours is only one of countless societies throughout human history, and not a particularly representative one.