Apparently some like Patton couldn't understand that either.
Hitler and his henchmen are delusional by this time. They seemed to forget they attacked and occupied Western Europe before they attacked Russia. They forgot unleashing the Blitz on Britain and very nearly invading it. They forgot their ally's sneak attack on the U.S. Pacific Fleet and that it was Germany who declared war on the U.S.
And the fools have been making their main effort for the last nine months in the West while neglecting the East where Guderian told them repeatedly the Russians were amassing a vast army.
In military matters Hitler really was at heart just a Bavarian corporal.