There is absolutely a difference for fascism and Fascism. Google it, look in any dictionary, Wikipedia. This is a thing historians and political scientists understand.
The Fascism movement is where we get the word, from Mussolini's Fascist movement. When you capitalize it you are talking about the proper noun Fascism as a movement, you are talking about a very specific identifiable and isolated thing. Mussolini's movement
But fascism as a concept moved beyond that movement. It is not limited to Fascism and in fact doesn't even entirely match with Fascism. These are just truths not my opinion.
The guy I'm talking to doesn't understand either and clearly hasn't googled them at the minimum. He doesn't understand it and that is the entire point, this man wouldn't know a fascist if he voted for one.
https://en.m.wikipedia.org/wiki/Definitions_of_fascism
https://www.merriam-webster.com/dictionary/fascism
https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095811414
It isn't the same. I don't know Italian or your extent to understand English but capitalizing in English matters, proper nouns are a thing, google them.
For example: Apple and apple, march and March, moon and Moon, Pole and pole.
Those all change meaning when you capitalize them. Same stands for fascist and Fascist.