Brandon, thanks for entertaining me with your voicemails last week (or has it already been two weeks?) at work. I got busy and never responded. In fact, your Boos still haven't been uploaded! I'll fix that now. Consider this a preliminary rambling response. I didn't do any research or re-watching before writing these maybe ill-informed opinions. I think that my general impressions here are right. Correct me if I'm wrong.
John Ford would have been 20 years old when he agreed to a bit part in a film directed by one of the hottest directors in the world. Coming from Maine in a pre-media-saturated world, I doubt that Ford had any great notion about what a "Klansman" was. Ford had just moved to Hollywood the year before and was trying to break into pictures by working in his brother's shadow. Do we really need to think that he was a terrible racist to take a bit part in what was one of the biggest films of the time when he was just starting his career? Even if he knew exactly what he was doing, so what? I bet you also made bad decisions at age 20. If we're going to talk about Ford's treatment of "blacks" and "reds", then we ought to at least look at the man's own mature films.
I haven't seen as many Ford films as you guys have, but I have a hard time seeing him as any sort of black-hating racist. He gave work to Stepin Fetchit and others when others in Hollywood wouldn't go near any "black" material if it wasn't blackface or hard mockery. The Stepin Fetchit roles in Judge Priest and Steamboat Round the Bend are both sympathetic comic relief parts. They are not at all representative types of all black men. That would be like saying that all Oliver Hardy films are racist because they tarnish the image that we have of all white men. I'd have to re-watch them, but I remember Fetchit's character in both films (but more so in Round the Bend) as likable and decent. If Fetchit is a Coon, then Rogers is only a thinly veiled society version of the same. Maybe there's some stereotyping going on, but no more so than in any Laurel & Hardy sketch or Abbott and Costello routine. Neither of these films are focused on 'realism' in any way. I also remember reading that Priest originally had a scene featuring the Judge putting a stop to a lynching of a black man, but the studio took the scene out because they knew they wouldn't make any money in the South if they left it in. I would never say that Judge Priest is entirely uncomplicated in its treatment of "race relations", but Ford does have Will Rogers and Stepin Fetchit acting as friends in a time and place in which this wasn't the easiest of relationships.
As far as treatment of "Indians" go, I'd say that Ford's record is even better. It's easy for us to forget how terrifying it was for white settlers heading West to be attacked by Indians. Most average folk were innocent in their actions toward the natives. They were defending their lives and trying to make a new life for themselves in a new land. In a world before mass communication, they were living in terms of their environment based on the best knowledge they had, including often being told that the tribes were savage and ruthless. And, to be fair, the tribes often were savage and ruthless. Even the cavalry men were often honorable (though, of course, not always). They were following orders and trying to live up to an ideal. It was the U.S. leaders who were constantly breaking treaties and acting wickedly. The men with money in the game were the men betraying all others, both white and brown and black. Again, I don't think that Ford is often concerned with 'realism', but I do think that he was trying to explore what it meant to be an American forging an identity amid an often violent and antagonistic land.
It is important to keep in mind that John Ford was an Irishman. His father was an immigrant from Ireland. So, Ford himself wasn't ever a slave like many other Irish in America (http://www.amazon.com/White-Cargo-Forgotten-History-Britains/dp/0814742963), but he lived in a land with a history of hating the Irish, in which Irish men, women, and children had been enslaved and were rarely thought of as anything but inferior, if they were thought of at all. Depending what part of the country you were in, to be Irish in America was not much better at times than being African or Asian. We can't imagine this kind of hateful "white on white" racism, but it was indeed commonplace. Today, the Irish have come a long way in that now we only dismiss them as fun-loving drunks instead of as subhuman inferiors. What is amazing is that John Ford loved America in spite of this complicated history.
In conclusion, Tarantino is a freaking idiot. I'm not sure if he's ever seen a John Ford film.
I'm now going to post Brandon's Boos, listen to them again, and re-read the Kent Jones article: http://www.filmcomment.com/article/intolerance-quentin-tarantino-john-ford