They simply became dependent children again

"Early theorists of group psychology had tried to explain why men were so sheep-like when they functioned in groups. They developed ideas like "mental contagion" and "herd instinct," which became very popular. But as Freud was quick to see, these ideas never really did explain what men did with their judgment and common sense when they got caught up in groups. Freud saw right away what they did with it: they simply became dependent children again, blindly following the inner voice of their parents, which now came to them under the hypnotic spell of the leader. They abandoned their egos to his, identified with his power, tried to function with him as an ideal."