Mass sterialization and clean prison camps actually make it worse as it's horrifying evil disguised in self-aggrandizing benevolence.
Generally, my view of Richard Grey is he's the self-appointed solution to a probem which no one asked him to fix. He wished to create a end to war and conflict but to do so did a war which is probably the worst since the Great War and since in the Fallout universe. His views always had a self-justification or an excuse or a way to rationalize them but that doesn't mean any of them were right.
His "peace" was enforced with psychic powers in the minds of all Super Mutants and was unnaturally enforced. It also meant the end of human culture and the possibility of change, which is the hallmark of evolution. It also requires him to enforce that peace for eternity as Big Brother, in the minds of his followers for eternity.
I don't think he's a Hitler figure at all. Instead, I see him as the worst embodiment of, of all things, communist utopianism.