"Heard of the term "Red Fascist"?
Call it with the correct term, "Communist". Which actually, predates Fascism (1917 vs 1922, and Mussolini came from the Socialist Party - in Italy the Communist one separated from it only in 1921) - and paved the way about how a modern, large scale dictatorship should work, including tactics and propaganda.
In many ways, Lenin showed other how to obtain power and set up a totalitarianism. Other followed, albeit with slightly different ideas.
It's no surprise, for example, that in Italy many Fascists easily became Communists when Mussolini fell. On the other way, we see in Russia many switching easily to far right ideas after being raised in what was the far-left state.
In this case, extremes are far more much alike each other than moderates.