The Bavarian area of Germany?
Hitler was Austrian and at least in Germany people use this saying with Italian Mussolini style fascism or even just German
I know it started in Munich but calling it Bavarian in origin is a bit unusual
It’s just a skooch of humor, not an academic treatise.
Oh, I see you’re in Germany. Well, that probably didn’t come across the same as it did here. Sorry - carry on.