Yes, those are the choices, and they are both the same.
Obviously FDR and Churchill didn't think so. We allied with communist Russia during WWII to fight the Nazis, so Nazism was perceived as a bigger threat to our way of life than communism was, when push came to shove back then. It was only post WWII that the cold war began in earnest.
I am no defender of communism, but if you asked me to choose, I'd rather deal with communists than I would Nazis.