There are a variety of biologically rooted conditions that predispose people to violently anti-social behavior and there's no reason to believe these conditions would somehow disappear in a more egalitarian society. People with various conditions like narcissism or anti-social personality disorder exhibit measurable, readily viewed abnormal brain states and show pervasive patterns of disregard for the rights and wellbeing of others regardless of their material circumstances or experiences.

Individuals with these conditions still vary widely; Some will never commit overt acts of violence, while others will engage in serial acts of violence and abuse. But the underlying causes are biological and generally cannot be addressed with therapy or psychiatric intervention. There's actually a notorious phenomena where putting some narcissists and people with ASPD through therapy teaches them how to better abuse and manipulate people while evading consequences by giving them a better understanding of human emotion and psychology.