@Khandro
//Look to history; //
Yes, let's do that.
//the Mongol hordes,//
Someone recently found an ancient tree, in Mongolia or nearby, which showed weather-related stress (stunted growth) coincident with the medieval warm period. Possibly a reach but someone has already speculated that Mongolia underwent a sustained drought, which would have ruined grazing for a horse-heavy culture. They were nomadic, in any case and I can extrapolate that they drifted westwards, got a difficult reception, discovered they were good at fighting and just never stopped until they reached Poland.
If you can accept "Viking" as a verb, not a noun, then that is basically what they did. Pagans though. (by all means fact-check me on that)
// the USSR, //
Mostly Joe Stalin but the stuffed shirts who did the deeds must have developed a taste for it as they carried on shooting inconvenient people for decades after he keeled over.
// WWII, //
The Holocaust must have had *something* to do with centuries of hatred between Christians and Jews. Hitler may have got his ideas from the Russian pogroms, in "The Pale of Settlement", circa 1860s (??)
"Hitler was Catholic" is a worn out old chesnut. Let's try to say something new,
like "Germany, Austria and the Sudetenland were Protestant/Lutheran and all cheered and saluted when Hitler preached hatred against Jews".
(Although known outspoken types existed, they tended to get 'spirited away', in the night and never seen again).
//
Pol Pot,
//
The psychopaths' psychopath. Intellectuals - heck, anyone who wore glasses, really - were top of his hit list. Open admission that he was far from the smartest person in his own country.
//Maoist China, //
Hmm, I need to read more. Generally, if all we get to see is the old propoganda posters then we know it was a closed-door regime and nobody has a clue what really went on.
//
and more,
//
Meh, you've given us enough to work with, for the moment.
// all secular //
All despotic regimes, run by psychopaths, with no moral compass. Living for the moment; doing whatever they pleased and * everyone else.
Past performance does not guarantee future results. If our brush is painting too widely, do - please - tell us how to be more specific about who we accuse, of what.