So I'm going to argue against Paul's reign and Leto IIs reigns as "facism." Facism involves a lie, and a focus on identity. It forces you to do ineffective governing on the actual underlying issues.
Paul and Leto II were more like "Absolute Theocracy" in the way that their mysticism was observable and they had god like powers. It was also not Paul directing the subsequent crusades against the imperium, it was the fremen, who were zealot warriors.
It was also not Paul directing the subsequent crusades against the imperium, it was the fremen, who were zealot warriors.
Actually he did - because he saw in a vision that not directing the Jihad would lead to even more death and destruction
Both Paul and Letos reigns defy categorization in a lot of ways simply because a lot of the reasons behind their rule and mechanisms behind their government rely on fictional things (mainly prescience)
I do agree though that Fascist probably isn't the best label here - certainly it was a flavor of totalitarianism in any case
Generally speaking the political system pre-Paul is feudal, and the Arteides happen to be one of the good royal families, ruling Caladan with benevolent technocracy and power which they don't really have to use. Contrast that to the Harkonnen who bleed their fiefdom to the bone, imagine North Korea but competently profit-oriented. Both approaches are considered perfectly fine as far as the Emperor is concerned.
The Bene Gesserit have more important things on their minds than giving a fuck about how the serfs live and, just like the Spacing Guild, are a religious/scientific cult (having, respectively, a messiah prophecy and a goddess. And Norma seriously out-powerlevels Leto and yes Brian Herbert is worth a read even if the prose sucks fite me IRL)
In my head Paul (and the Fremen) are more similar to the Mongol Empire, violent and conquering but not fascist. But I stopped reading after part 2 and it has been a while