Well... you and I both agree that a wide range of various human civilizations and societies are extremely f'ed up!
But I think civilizations become insanely messed up for other reasons than you do... such as:
Severe and ongoing led-poisoning in Ancient Rome from water-pipes and wine-fermentation vessels...
Psychotic individuals gaining political power...
Unbridled greed for wealth and/or power...
Herd mentality...
The failure of "good" people to step up, and speak out against vile, archaic, enslaving ideologies...
Territorial disputes (whether legitimate or not)...
etc...
I could go on and on... but I guess I'll stop here.