There's a whole lot of 'new' archaeological and anthropological information on old or ancient human cultures that were not what you describe. Over tens of thousands of years even. Of course eventually they got trashed by aggressive autocratic patriarchies, colonizers like us - that's really the problem. Plenty of options and precedent for human culture that is egalitarian and relatively peaceful. The trick is to keep the 'barbarians' out and still hold an egalitarian and peace-based culture.