Or maybe.....politics had nothing to do with it and "Greatest Show On Earth" was given recognition for being an impressive spectacle film that long-term preserved what is now a vanished piece of Americana (the circus under canvas).
I think the Academy's real mistake was the previous year with...
Got my copy and enjoyed it. DeMille preserved on film a piece of Americana that has now vanished and for that he is owed a lot of thanks. And Jimmy Stewart deserved at least a supporting actor nomination.