Okay, I'm going to attempt to clarify this one last time, because I've been thinking about it for a few days now. One of the dictionary definitons of "black" is "figuratively, dismal, gloomy, sullen, forbidding, or the like; destitute of moral light or goodness; mournful; calamitous; evil; wicked; atrocious." Shakespeare used the word to describe black "deeds, thoughts, envy, tidings, despair." The word "skin" is described in the dictionary as a word meaning several things other than "the external covering... of most animals..." Without quoting all of the possible meanings word for word, I'll just mention that it is used to describe the outermost layer of a number of different items, from the shell of a ship to the skum that appears on boiling milk to the surface of a pearl. Essentially, it's the layer that is most readily visually apparent.
We often use the word "dark" in reference to certain types of comedies which, while funny and entertaining, have a sinister side. Many people, when viewing a photograph of certain criminals who have commited an unusually vile crime, will comment that they even look evil. They have a dark (i.e. evil) appearance. Oftentimes, it's a look in their eyes or just their overall countenance.
To me, the "skin of blackness" symbolizes the overall look of darkness associated with a particularly base, depraved or menacing persona. I think it clearly does refer to appearance, but not to the actual color of the Lamanites skin (which was virtually identical to the skin color of the Nephites, since both groups were of Middle-eastern descent).
If you still think it's a racist statement, I guess we'll just have to agree to disagree.