Another article on this issue that appeared in the Boston Herald contains a few more reactions to Romney's statement:

http://news.bostonherald.com/localRegional/view.bg?articleid=150679

One comment in particular caught my attention:

Maurice Lewis, a former Boston television reporter who
is black, said of Romney’s choice of words, “I just think
it’s reflective of how he sees people who don’t look like
him. Words like tar baby and pickaninny are deeply rooted
in the segregation of America. They don’t have an
ever-changing, ever-expanding meaning.”

What really made this comment stand out for me was the same thing that sparked my original post: the notion that the commonly understood meaning of this phrase is a slur. These comments, and those posted in this forum show that this is true for some, and not for others. Do dictionaries exhibit bias by not mentioning the negative connotation of the term?

Perhaps the difference in meaning falls along regional lines, or perhaps it's racial, I don't know. I'd agree with Lewis that these phrases are deeply rooted in America's history of segregation and slavery, but I think the notion of any word having a static meaning is absurd. Some change more slowly than others to be sure, but language can be as fluid as a glacier, or an ocean.