I first heard of him back in the seventies in a European History course while we were focused on WWI.
It's been many a year, but as I recall he was mentioned due to the influence he had in Italian anti-War circles that were working to undermine the war effort. I'm not sure, but I think he wrote or was quoted in some of the leaflets they passed out encouraging troops to desert or go on strike the way some French units did.
I'm positive he used to be mentioned in several European History courses and someone I knew had to read all about him for one of their courses, but what they call History has changed so much since the seventies that I doubt they bother with the amount of detail that used to be the norm. Now, apparently, they go over various "psychological factors" and sociology while ignoring individuals who made a difference as much as possible.