I take this piece as a clear warning to Nazis, but a warning with no threat. By contrast, if I understand correctly, you could not be both Communist and Catholic at the same time.
Let me put it this way: were any Nazis ever excommunicated, either for their Nazi ideology, or for their genocidal behavior? I can't think of a one, including Adolf Hitler!
Every NAZI who was baptized Catholic and who by deed, word or belief rejected the faith they were baptized in was automatically excommunicated:spiritual suicide if you will.
When a coroner officially pronounces a corps dead, it doesn't mean the corps was alive until that point. Dead is dead with or with out the "official" recognition; same with excommunication.