The lesson no one seems to be taking away from l'affaire Shirley Sherrod is that in the United States it's still legal to be racist. The Constitution protects the right to think racist thoughts and express racist ideas; the only thing legislation since 1964 bars is acting on these thoughts or ideas.
Even in the so-called Fox News network's truncated and out-of-context video of Sherrod's statements, she was perfectly within her rights to express a dislike of whites. That's not what she was expressing in the full unexpurgated version, but if she had been, it would have been legal.
No civil servant, employer, supervisor, renter or seller, and so forth, may legally refuse goods, services or opportunities or rights to anyone merely on the basis that the individual is white, Christian, British, male or (in some states) heterosexual. That's the law.
However, you can caricature and even express a hostile disposition in your mind and in your speech against any legally protected group. Neither the civil rights movement, nor much less Congress, ever thought the government could ever actually change minds by law -- only actual external behavior.
The psychologist William James was fond of this approach: force yourself smile and you'll feel more lighthearted. It's a very American approach to social problems such as racism.