Dune asks “what way after the collapse of industrial capitalist democracy” and the Fremen, working with the ecological education and leadership of Pardot and Liet Kynes, realize they can terraform the poles of Arrakis and preserve the desert for sandworms, allowing for equitably shared out prosperty and ending “the system of mutual exploitation and pillage” without even needing to directly contest Imperial authority.

Paul decides he’d rather hijack their energy for his own purposes and sets himself up as a new emperor, using ideology to distract the Fremen from what would arguably be a better solution to their problems. This is so Paul doesn’t have to accept the loss of his relative position within the Imperium (it’s discussed at several points how Paul and Leto both explore, and reject separately, the option of taking House Atreides out of the Imperium entirely, thus avoiding a fight with the Emperor and House Harkonnen; the whole struggle isn’t life-and-death, it’s status-and-death). Paul fights to become an Emperor so he doesn’t have to die in obscurity as a rogue aristocrat. That’s it. So there is an element of threatened identity there or identity-based resentment there.

His mystical visions show him about twenty different pathways and he rejects all but the most violent one, so I think there is a lie involved in his state ideology. It’s not that he doesn’t have prescience, his “great lie” is that his prescience told him he had to become Emperor.

Overall, the book explores different pathways out of the collapse of our modern society and imagines a horrible future where we don’t uproot structural inequality and violence and allow modern techniques of social control to blend with outright feudal social relations in the aftermath, and then we don’t demolish it. I get why people call Paul fascist.