This is literally a plot point of Strugatsky (of Stalker fame) novel (and movie) Hard to Be God. Communist Earth finds a planet of human-like aliens stuck in medieval ages but decides to help only by influencing the politics with spies and shit, because going ham would be “robbing people of their history”.
The movie is great even if more artsy than the novel. I’m not sure how many of their books are translated to english but they are pretty cool.