Thomas and others have done a better job than I could hope to do taking apart some of the things that stood out the most as wrong.
The central idea though of reoccurring themes in history is, well kinda eh. It isn't wrong because certain themes like Umberto says, tradition, notions of "the people", do have their origins fairly remotely. A lot of fascism is "eternal" in the sense that the motivations behind it are eternal. People will never stop feeling grievances or the desire to return to a former glory. This has always been the case. It isn't that there were elements of the fascist in the past it is that there are elements from the past in fascism. Which is hardly a revolutionary statement. Ultimately he is trying to make the case that there are browns under the beds and we have to be vigilant that these subterranean forces don't re-emerge.
I love this kind of thinking from the left because it reveals their belief that the dangerous revolutionary right is some kind of elemental force. Almost suggesting that it is human nature or at least something which we're naturally susceptible to. Which I wouldn't even disagree with honestly.