Am I really better, morally, ethically, or spiritually, than someone who _doesn't_ know how to patch an Oracle database? Even the landscapers blowing leaves into the street next door know that forcibly asserting ownership of another human being is wrong, yet this seems to have escaped the superior intellect of "the Founding Fathers" (who my own ancestors, having emigrated as impoverished peasants from Italy at the turn of the last century, had no connection with: something they sadly later forgot). Jefferson was a slaver, an oppressor of the weak, and a rapist, and the majority of high society and Congress were (and are) accessories before and after the fact.
The US Civil War was an aberration, because it was one of the few times that the schemes of one part of the oligarchy coincided with the growing disgust of the commons with a horrendous institution (chattel slavery). The moral outrage over slavery seen in the diaries of Union soldiers didn't disappear with the Confederacy's defeat, but the interests of the oligarchs worked against the success of Reconstruction and the later imposition of Jim Crow (whose legal framework provided inspiration for 20th century fascism in places like Germany).
We loosely categorize ancient Rome as a civilization. It was an oligarchic slave state, as were the later European and American empires. The main difference between them seems to be the mechanisms of slavery employed. In 21st century America we still have a feudal model of governance in most workplaces, and in governments bought and paid for by unfettered oligarch cash, the will of the common people, to the extent that its expression is able to pierce the corporate media bubble, is mostly ignored or explained away.