It's been clear since the Progressive era of the early 20th century that lefties have always been fond of fascism, communism, Nazism and any other form of socialism. When WWII broke out, they knew they had to dump their love for all of those systems of government.
They figured that because we were fighting the Nazis and the fascists that they would push that off on the right wing. It was the beginning of the left's game of guilt transference. Ever since then every single screw up the left makes gets immediately blamed on the right.