I'm reminded of the evolutionaey biologist E.O. Wilson's comment on Communism - "great idea, wrong species".
The more we understand about our closest cousins, the primates, it's plain to see that their "societies" aren't all peace, love and understanding. There is war, rape, infanticide, murder, jealousy, hierarchy, social exclusion, resource hoarding and unequal distribution, etc etc.
Any social and political theory that only works if EVERYONE is morally perfect, psychologically stable, and emotionally intelligent is laughable.
The broad sweep of History, and our own lived experiences, show us over and over that NONE of these things are true for ANYONE over their lifetime.
Everyone gets angry, lies, makes bad decisions and hurts other people at some point in their lives, and some make an entire lifestyle out of being that type of person.
Economics and game theory have loads of concepts like "the tragedy of the commons" or "the freeloader problem" or "deflection" (eg in "The Prisoners Dilemma") that talk about how expecting people to always choose the group over their own best interests is doomed to failures over the long run.