I think there are plenty of reasons other than self-censorship why someone choosing to write about a whole bunch of touchy political themes might think that someone interpreting a draft of their story in an entirely different light from the intended one might be a story problem rather than an editor problem. Especially if their response is to issue further drafts full of commentary on respective cultures, the virtues of national pride vs assimilation etc, not to drop it and write a story about saving the planet or talking tigers. Similarly, it might be very pessimistic to assume a review awarding a story "Editor's Choice" is an attack on its appropriateness, not great idea, but a bit liable to misinterpretation in current form

Either way, the ending the author actually ended up with feels a lot stronger than it might have been had the protagonist concluded that rosy revisionist history actually was the solution to all a nation's problems or that he couldn't possibly feel any sense of belonging in the US.

> Also, I think it would be very optimistic to assume an editor is deploying the word “problematic” about your story as anything other than an attack on its appropriateness and validity.

It's also plausible that it's "problematic" because the white savior theme has been so overdone it won't make the story interesting or stand out in any way. That's certainly problematic from a writer's perspective.