You are also really stupid, of course it is religion related.
Stalin and Riddler didn't declare a war on Jews and Christians.
Stalin was removing extremism of religion altogether, and Riddler convinced the Germans that the jews are to blame for the problems, as they were mainly non nationalists that controlled much industry in the country.
was political tools to bring armies together.
people who actually believed ww2 had anything at all to do with religion is a fool.