I’ve long thought that Hitler’s movement was anti-Communist. Communism was sweeping Europe and Hitler came to power by opposing it. It tended to scare people that they might wake to being hung by a mob.
In the end, you are largely defined by your opposition, especially when you lose. So Hitler is labeled a Fascist by the Communist. It doesn’t hurt that the world’s press and intellectuals are essentially Communist, and happy to apply the appellation.
The real difference between Adolf and the commies was his rejection of their touted “internationalism”. Instead of a class struggle, his was a nation struggle with the Germans struggling against “inferior” peoples.
There’s even less difference between Mussolini’s version of fascism and communism.