Weren't Facists/Nazis and Communits enemies? Didn't the Catholics lend support toe the National Socialists?
History shows that to be a false comparison. Hitler treated both the Kremlin and the Vatican with the same duplicity he used against everyone else (except, perhaps, Mussolini and Tojo). Saying that the Soviets were blameless while the Vatican was culpable is shameless double-talk.
Stalin assisted Hitler with the invasion of Poland. Germany took over the western part, the Soviets took the east. Stalin and Hitler remained military allies until Hitler unleashed Operation Barbarossa, his largest attack of the war, against his former supporter. Though no doubt suspicious of each other, Germany and the USSR were not enemies until the German invasion.
The Reichskonkordat Pius XI agreed to with Germany in 1933 was one of twenty-one such agreements promoting religious liberty. It was soon clear that Hitler had no intention of honoring it. Pius XI effectively rescinded the concordat in 1937 by issuing Mit Brenneger Sorge:
... We shall continue without failing, to stand before the rulers of your people as the defender of violated rights, and in obedience to Our Conscience and Our pastoral mission, whether We be successful or not, to oppose the policy which seeks, by open or secret means, to strangle rights guaranteed by a treaty ...
... Whoever exalts race, or the people, or the State, or a particular form of State, or the depositories of power, or any other fundamental value of the human community - however necessary and honorable be their function in worldly things - whoever raises these notions above their standard value and divinizes them to an idolatrous level, distorts and perverts an order of the world planned and created by God; he is far from the true faith in God and from the concept of life which that faith upholds ...
Then in September 1938 Pius XI said:
No, no, I say to you it is impossible for a Christian to take part in anti-Semitism. It is inadmissible. Through Christ and in Christ we are the spiritual progeny of Abraham. Spiritually, we [Christians] are all Semites.
This was said by a religious leader, who commanded no army and no navy. About two weeks later, the leader of a world-wide empire defended by a strong army, navy and air corps agreed to give Hitler the Sudetenland, territory belonging to a country with no role in negotiating that concession.
So, who really played the dupe for herr Shiklgruber?