They single out a disaffected middle class as a key fascist constituency because that’s historically accurate. The Nazis in particular were built on the lower rungs of the middle class who had some status to lose, but not enough to fully insulate themselves from economic swings. Think small shop owners more than factory owners.

Poorer laborers during that time were more likely to be swayed by the communists, who had more to offer poor workers. Fear of these same communists helped also drive upper class tolerance for nazis and fascists too.