Sounds to me like a case of not understanding the true cause leading to a case of The Fox and The Grapes (I can't achieve that, so I decide it is bad), leading

Sounds to me like a case of not understanding the true cause leading to a case of The Fox and The Grapes (I can't achieve that, so I decide it is bad), leading to animosity. And then they justified that animosity by mixing it into their beliefs (religion - but one can argue the religion isn't a necessary component, just look at totalitarian communist regimes). Yes, probably oversimplified, but I still just see known common psychological traits in action. I'll take a look at your references later. Yes, ideology drives the direction. I'm very well aware of that and agree fully. But which one spread and how they spread and how popular they bevome largely depends on factors like, timing, who it spreads to first (influential people or not), the prior context, etc... Different contexts make it more likely for some ideas to spread but not others. Comparisons to virology is actually very applicable. And a crisis is a typical situation that amplifies the probability of some idea spreading broadly and taking root, and the context and circumstances is part of influencing which ones.