Below is a photo of clergy being forced to participate in a rally. I forget where and when it happened but if you look at their faces they aren't very happy about it.
Again, note how unhappy they are. They were forced to participate and salute.
There are a lot of conspiracy theories about the church's role but it was coercion. Reinhardt Heydrich and Heinrich Himmler were notoriously anti-christian particularly against Catholics.
And then there were the Ustashe in Croatia, and Father Tiso in Slovakia.