During the French Revolution’s “Reign of Terror,” those accused of not being true enough to the cause were publicly beheaded. To unify the Communist Party in Russia, the Stalinist purges did much the same. Mao used the equivalent tactic with his Cultural Revolution. It’s a tried and true technique. People who didn’t want to get swept up in these eradications learned quickly to not just embrace the political philosophies championed by the new power structure, but to chant the new mantras louder than the person next to them. This way they can show they’ve always been on the winner’s team,...