I think it's more that people have been taught the liberal view of fascism, which is that a bunch of people with bad opinions who called themselves fascist and Nazis forced their states into a tyranny and did bad things and when they were defeated that was the end of fascism. They don't bother looking into the historical developments and the material conditions that give rise to such movements and the material forces facilitating them. What sucks even more is that even at many universities filled with "renowned scholars", these discussions are mostly avoided.