via WSJ:
Mao unleashed university and high school students to weed out enemies and hold them to account. The students became the paramilitary Red Guards. They were instructed by the party to “clear away the evil habits of the old society” and extinguish what came to be known as “the four olds”—old ideas and customs, old habits and culture. “Sweep Away All Monsters and Demons,” the state newspaper instructed them.
With a vengeance they did.
In the struggle sessions the accused, often teachers suspected of lacking proletarian feeling, were paraded through streets and campuses, sometimes stadiums. It was important always to have a jeering crowd; it was important that the electric feeling that comes with the possibility of murder be present. Dunce caps, sometimes wastebaskets, were placed on the victims’ heads, and placards stipulating their crimes hung from their necks. The victims were accused, berated, assaulted. Many falsely confessed in the vain hope of mercy.
Were any “guilty”? It hardly mattered. Fear and terror were the point. A destroyed society is more easily dominated.