I’m not saying there isn’t a difference, but to suggest it’s not even an ethnic slur, ESPECIALLY IN THE CONTEXT OF DESCRIBING AMERICAN INDIANS, stretches credulity just a little.
I tend to agree with @anon15383236 that the difference has mostly to do with the fact that blacks have very successfully lobbied for recognition of their shared humanity, whereas American Indians have not been as successful in terms of public relations.
The N-word and the S-word are used equivalently, though: to try to deny the respective groups rights, autonomy, and recognition. In one case because they’re “just <n-words> and not fit to govern themselves”, in the other case because they’re “just <s-words> and not capable of properly improving the land they live on.”
