By who? Is there a reason for this?
Fascism's self-description is basically just the motto "united we stand, divided we fall". It's right there in the name. As a philosophy, I know it best for strict intolerance of public dissent. That sort of thing undermines unity.
And that's pretty much it. I would have said that "fascism" in modern American usage had lost all meaning other than as a generic term of abuse; I would never have guessed that it was supposed to mean "the opposite of communism, whatever that might mean". "The opposite of communism" is usually considered to be capitalism.
But there seem to be many good correspondences between Chinese practice today and original, Mussolini-style fascism.
First and foremost, by the inventors of fascism themselves, as I tried to show in some stealth edits in my comment above.
It's a bit like saying Tom Cruise isn't a real scientologist because Xenu doesn't exist.
The two seem to always be found near each other.
"Fascists" is probably not a good description of the Chinese Communist Party, since Fascism is widely regarded as always and everywhere the diametric opposite/enemy of Communism and Communists. Examples of this include [0] and [1] and [2] and [3], which are the results of me googling "is fascism the enemy of communism?" for 5 seconds. Probably you mean "Totalitarians" or "Statists" or "Authoritarian Governments" or something like that.
This is pedantic but lots of the discussion downthread seems to hinge on this point of equating "Chinese Communists" with "Fascists," and that's imho a totally false premise.
Oftentimes people say things like "Well the Chinese are commies in name only" and similar, and this might be semi-or-mostly true, but it's a bit of a leap from there to calling them fascists.
[0] "Mussolini, with his anti-Communist doctrines..." from https://en.wikipedia.org/wiki/Benito_Mussolini
[1] "In Hitler's mind, communism was a major enemy of Germany ... Hitler claimed that his singular goal was to assist the German government in "fighting Marxism". Marxism, Bolshevism, and communism were interchangeable terms for Hitler..." from https://en.wikipedia.org/wiki/Political_views_of_Adolf_Hitle...
[2] "Fascism is often considered to be a reaction to communist and socialist uprisings..." from https://en.wikipedia.org/wiki/Anti-communism
[3] "...in the early 1920s the Nazis were only one of many nationalist and fascist political parties contending for the leadership of Germany's anti-communist movement" also from https://en.wikipedia.org/wiki/Anti-communism