Of course Marxism is secular.
My point is that Marxism and Communism are characterized by much more important things than their anti-religious elements. Lenin and Stalin butchered millions of people for reasons that had nothing to do with their or Marx's views of religion. They were murdered because they refused to give up their land and homes to the state. I happen to believe that Nazism and Communism were very bad things but the reasons why have nothing to do with religion and everything to do with Marxism and Totalitarianism.
My problem with Prager is that, by inference, he is equating secularism with Nazism and Communism. That is simply a gross over simplification and, by inference, paints religion as the only alternative to totalitarianism.
And your missing Prager’s point, which is dead on, that secularism is required for Nazism and Communism. He never stated that it was the only component, or the most important component. He just stated that it was a requirement for those systems.
And that is absolutely correct.