1. Under Fascism, private individuals own the businesses and the government controls what the businesses do. Under Socialism, the State owns the businesses.
2. Fascism lost WW II, and got all the bad publicity. Socialism did not lose WW II, and thus escaped the bad publicity.
Actually, the leftwing NAZI Socialists DID lose WW2
N.A.Z.I. = National German Socialist Workers Party
You can't spell NAZI without Socialist...