is there a good word for this phenomenon besides witch hunt? I'd say it's a purity purge. You become convinced that there is unknown evil infiltrating your group and start a witch hunt for it. But it's hardly a new concept. Very common in American culture.

So is this why you don’t tend to see this Mcarthyist attitude popping up in other countries? I don’t know though, it feels like Westerners/Europeans are prone to it as a whole, I mean just look what happened during the time of the Bolsheviks and the Nazis. I think it’s just that extremist ideologies as a whole that trend towards scapegoating tend to be prone to this sort of witch-hunting because it removes objective reasoning and encourages anger & resentment amongst the populace which just clouds judgement.

Rather than a purity purge I feel a better name for these sorts of ideologies is Scapegoatism. The extremist leader at the time rises up and identifies either a particular sort of people and/or concept that is to blame for all of the ill in the world and stirs up the mob to take action to eliminate it at all costs if they want to see a rise in their standard of living.

Previous historical targets were Witches/The Jews/Monoarchy/Capitalism and yes, even Communism during the McCarthy Era. Now the very concepts of Power and Oppression itself is the newest scapegoat up on the chopping block in today’s Cancel Culture environment.