Because the Nazis lost spectacularly, thus bringing shame upon socialism. So they had to be misnamed and shoved out from under the collectivism tent, lest people see the inherent evil in collectivism at large.
Because the Nazis lost spectacularly, thus bringing shame upon socialism. So they had to be misnamed and shoved out from under the collectivism tent, lest people see the inherent evil in collectivism at large.