The reality is human beings just aren't intelligent enough to form long lasting social orders because too many people have negative evolutionary characteristics they've inherited from the past. Our primate psychology is at the root of everything regardless of what collection of words and labels one flies under. The biology is still there.
Those negative characteristics are only negative in the context of forming long lasting social orders (really only in the context of forming long lasting egalitarian social orders -- dynastic empires last longer than most of our social structures). They are extremely positive in the context of the affected individuals and in the case of avarice, they are beneficial to the affected's offspring (and their offspring, and so on). There is extreme benefit to be had from sabotaging the social order and norms.
We humans are intelligent enough to form effective and equitable social structures, we just don't have the collective stomach for removing the saboteurs from our society. So we/they continue to undermine every system we devise.