As I've mentioned, I definitely feel that the SPN debacle is symptomatic of a bigger issue in fandom, wherein we tend to bury our heads in the sand and forget that not everyone is as knowledgeable nor aware of things like privilege. But you're right that that in turn is symptomatic of a much broader issue that the U.S. has been carrying since…well, its inception, really.

That fanworks might include these tropes and stereotypes is upsetting and distasteful but not particularly surprising, given that they're informed by the media, and the entertainment industry even now clings doggedly to its white superiority complex. Most people in the US, I think, go to films or watch television shows wherein the white savior swoops in and saves the day for the noble but childlike natives, and it never occurs to them that there is any problem with it because our entertainment is so incredibly rife with these same tropes; because all we see is white, all the time; because the people in Hollywood want to seem progressive, but Hollywood itself is little different now than it was fifty years ago.

Ultimately, I don't know what to do about it, either, aside from conscientiously and carefully educating the people around me as best I can from my inherently privileged position. Just in the past five years or so I've learned a tremendous amount about that privilege and how it affects myself and others, and most of that is owing to other people talking about it. So yeah, I also definitely agree that continuing a dialog is important.