Take REH's Conan for example. While "mighty thews" might be from the pastiches, the rampant racism of the books certainly isn't. The fact that Conan, while a "barbarian" is a "white" barbarian and thus better than the other savages out there is not subtle, it's explicitly pointed out in some of the stories (Beyond the Black River is one). I remember reading on the Paizo blog referencing the Planet Stories line, that they are having some issues with this as well.
Never mind the John Carter stories, yeesh.
Just a response to note that Howard is hardly alone in this, and that, as "racist" as his stories are, they are actually far more enlightened than, say, Hemingway. Indeed, Howard's Picts are dark-skinned, and Brule, a Pict, is a heroic figure in the Kull stories. I think you're reading "better" into the stories that Howard doesn't indicate. Conan is just as savage, makes bad moral decisions which end up costing him, and has just as many problems as the other savage races. I think the discussion of politics with Howard is far more rational when considering barbarism vs civilization than race vs race. If anything, Conan is not a racist, having befriended and traveled with hosts of people of different colors and races. Conan even frees a bunch of black galley slaves as he recognizes that the bondage of slavery is inherently evil.
Beyond the Black Rive is often trotted out as evidence of Howard's racism, and probably rightfully so (his letters to people like Derleth and Lovecraft are far more damning), but it's still far tamer by comparison to many other writers of the time period. Indeed, Howard's Aesir, the whitest white characters in any of his stories are some of the worst villains and not heroes at all. They are the true "Aryan" culture and are depicted as bloodthirsty amoral savages.
Again, this isn't to say Howard wasn't racist. Society at large was racist at the time. Find me a famous black author from the turn of the century. This isn't to minimize the racial biases, but they have to be taken in context. Otherwise you create the same kind of argument that gets The Adventures of Huckleberry Finn banned from schools.
Heck, even Shakespeare was a racist and we still read him.
EDIT - Forgot about John Carter, where the good race of Barsoomian mankind is red, and the worst is white (the Therns). John Carter is by no means the "civilized white" leading the poor savage red people. In fact, he's just as much a war-monger and savage as they are and he's not the leader. He's the warlord, a chief in charge of war. He befriends a green man and marries a red woman. His children are red.