Mussolini, who started out as a socialist, certainly was anti-clerical and anti-religious in his early thinking. He later learned, as other dictators did, that he could use religion for his own ends, and did so.
I wouldn't say that fascism as such was anti-clerical or anti-religious -- Tiso, the Slovakian fascist leader, was himself a priest -- but I don't think Kagan was wholly off the mark in noting the anti-religious aspects of Nazism and Italian fascism.
I wouldn't argue with the rest of Ledeen's presentation. There's a populist trend in the world today that doesn't have very much in common with the fascism of the interwar years.
Then there was Croatia's Ante Pavelic.