Communism is a utopian class and stateless society.

Socialism is about worker owned means of production and abolishing classes.

Nothing of this has anything to do with fascism. In fact the original italian fascists where heavily sponsored by the capitalist class in order to protect their private property from socialist movements, which where reaching majority numbers at the time.

Fascism or similar totalitarian regimes gaining power is a REACTION to increasing unrest in the population do to the negative consequences of increased wealth concentration and inequality, which is a consequence of capitalism.