Pope Pius XI issues his anti-communist encyclical Divini Redemptoris. Pius XI is unequivocal in his condemnation of every facet of communism. He describes it as a satanic scourge, a false messianic idea, a pseudo-ideal, contrary to natural law, and a "fatal plague, which insinuates itself into the very marrow human society only to bring it ruin."
Communism attacks Christianity "with a hatred and savage barbarity one would not have believed possible in our age" and condemns all who resist to be "annihilated as hostile to the human race."
He also blames secular rulers for the existence of communism:
"There would be neither Socialism nor Communism today if the rulers of the nations had not scorned the teachings and material warnings of the Church."
This encyclical makes it clear that when Pius XI see something as dangerous and a threat, he is willing and able to use strong, direct language to condemn it and urge people to reject it. The fact that nothing similar is ever said about the Nazis and anti-Semitism indicates that neither are considered true threats or errors.