There have been plenty of other individuals besides Mussolini who made the same shift. Sorel, one of the originators of the myth of the general strike, was another notable example. Here's some information for further research:
Also, there are many unfortunate overlaps between certain kinds of primitivism and green anarchism with some aspects of fascist ideology, some of which are explored here:
(specifically my essay)
The issue isn't (or shouldn't be) about terminology, but ideology. Slogans (like Social War or Eternal War or even Class War) are meant to curtail thinking, which is why ideologists use them.
If you want to look at how (crypto?)fascism can still be attractive to a certain kind of anarchist, look at the popularity of "Fight Club." Regardless of too many fascist undertones in the book and the film (which, if you haven't studied at least a little fascist ideology and philosophy, are easy to [dis]miss), many anarchists find the story compelling.
Here's something I wrote to someone over on libcom:
"Fight Club contains a truncated critique of capitalism centered on credit schemes. Tyler's big plan is to destroy the buildings and the computers that house people's credit scores - presumably so everyone can start over fresh. That's not a critique of capitalism, not by a long shot.
I have studied fascist philosophy more than I wanted to, and FC fits into a particular strain of fascism: vitalism (feeling alive through action for action's sake, coupled with an elitist clandestinity, and a paramilitary ethos), sublimated homoeroticism (fighting is definitely homoerotic), a fear of and disrespect toward women, and unquestioned obedience to a leader (fist rule of Fight Club...).
It is a despicable little book, which has done quite a bit to derail revolutionary critiques of alienation and capitalism. I have had this argument with many of my comrades when the film first came out, and it pops up every so often in different places again and again.
It has nothing in it about class society and the reason radicals and revolutionaries want to abolish it. Without a class analysis of the inherent contradictions and unfulfillable hopes of workers and poor people, what you get is populism; and in the US context, populism mostly lines up on the Right."