The Communists were, as ever, absolutist totalitarians; the Nazis were surely strongly authoritarian, but not quite totalitarian. Religions, for example (except Judaism, of course), were neither banned outright nor particularly persecuted, save when a cleric would speak out against Nazism.
It’s easier for a Communist country to flip and become a Fascist one instead of a Democracy. This is what I think has happened in China and Russia.
On the contrary many Christians could and did find themselves interned very quickly for teaching out of the old testament, or for teaching of Herod's evil in the Christmas story. Religion was tolerated only as long as they accepted government approved doctrines. Read about Dietrich Bonhoffer, among many, many people whose shortened lives disprove your statement