Did you read my post directly above yours, documenting that undermining Christianity was an objective of the National Socialist Party?
You can also read there how the Nazis, in typical leftist fashion, dissembled and concealed their ultimate goals, so I'm sure they would not be above using superficial "religious" propaganda like your belt buckle in order to con and motivate the "rabble" in their army, many of them raised in Christian homes. Even so, there is nothing Christian about the buckle, and it bears the swastika, which is a pagan symbol. The eagle and swastika are Nazi Party heraldic emblems, not remotely Christian.
Jean-Fraud Kerry and Ted "Swimmer" Kennedy are nominal Catholics, but support abortion. Can we conclude from that that abortion is true Catholic doctrine? Of course not. The Church explicitly condemns it. Leftists of all stripes are expert phonies.