Re-reading the Name of the Rose recently, a substantial subplot involves the heretic movements that often wracked Christendom. It seems, looking at medieval and ancient history, that this sort of thing happened all the time! People would get swept up in an ideological craze, usually spearheaded by some charismatic preacher or figurehead, but often these movements had a life of their own, to the point that it’s not clear if these leaders were driving or being carried along by their followers.
Perhaps getting caught up in a memetic tide isn’t something new and unique to our modern social media landscape. Perhaps it’s something that just happens to humans when they’re together in large enough groups that reach some sort of critical point. Perhaps the mid 20th century western top down media landscape was an outlier of unusual stability and moderation and what we’re seeing nowadays with social media is actually the global village returning to form and being like a village.