In dune 2 (the movie) I feel that message was pretty explicit with Paul's internal conflict with heading south and chani's condemnation of it
In the books Paul compares himself to Hitler and Genghis Khan. I don't think dune has much to say about left movements specifically, just that blind worship is dangerous. The first Dune was written before the cultural revolution, however. Maybe Mao would have been mentioned if it was published a few years later
