Don't let the "ecology" shit fool you, the Whole Fucking Thing with Dune is just doing a goofy hegelian synthesis of eugenics and social darwinism, two things that are fucked up on their own and certainly don't get less fucked up when you combine them and add swords and precognition
Do you need both eugenics and social darwinism to be that fucked up? No, certainly not, as Herbert demonstrated in The Dosadi Experiment, which is basically Dune but with a protagonist I like more. Herbert was really obsessed with the idea that people subjected to brutal oppression would become more fit due to selective forces.