I think a better term would be irreligious. Nations with state controlled churches tend to have dead churches. Plus Europe was affected by modernism a century before the US. So many if not the majority of churches were not pastored by traditional/conservative Christians. There simply wasn't millions of Christians in Germany. The Christians that were there formed "the confessing church" to oppose the nazi. Einstein praised their efforts, commenting that the greatest resistance came from the least expected source. Einstein had thought that the colleges, unions and press, would lead the opposition to Nazism.