This trope has been going around again. So here's a helpful refutation of the idea that Dune is a "white savior" story.
The video is put together by a prominent black science fiction critic.
I don't agree with every point he makes. But the key ones are irrefutable for anyone who reads the books at all closely. Note that point 3 is a spoiler to those who have not read the books:
I would add that Dune is also NOT a simple left-wing story where a pure and noble native culture gets spoiled and/or "appropriated" by evil imperialists. Herbert shows that preexisting Fremen society was deeply flawed and unjust, and that many of its structures and traditions are themselves the products of past oppression and manipulation. But that's a subject for another post.