While it's not fashionable, the hard truth is that 99% of human history is the result of sheer stupidity and ignorance coupled to mindless emotional manipulation. Historians endlessly look for "reasons" why things happened but the fact is, most things happen by random chance. We then rationalize them as inevitable, post-hoc. We've more than sufficient evidence to support this proposition - even in the last 4 years alone. We humans love to pretend we do things for reasons, but the real reason we do nearly everything is simply because we're too stupid to imagine the inevitable consequences of our incoherent actions.