There are a fair number of older, white, "yellow dog Democrats" in the southeast who don't exactly have an equitable view of blacks. Remember, it was the Democratic party that tried to filibuster the Civil Rights Act. Many of them have (sadly) switched to the Republican party, but there are quite a few who haven't.
In addition, many elitists feel terrible about the 'plight of the African-Americans', but wouldn't actually talk to one unless they were cornered.
But 30%? That sounds awfully high.