How many books do you suppose have been written about this subject?
Think about how for hundreds of years, black slaves were not considered whole people. They were forced to work for no wages, sold away from their families, and had no freedoms -- not even the freedom to learn to read. Their owners, on the other hand "knew" they were superior to their slaves.
Now, consider that these attitudes were passed from parent to children to granchildren, etc.
Maureen Dowd, a New York Times columnist, stated Sunday that she believed that Rep. Joe Wilson who yelled "You lie!" at President Obama recently, really meant, "You lie, boy!" Although the Civil War ended almost 150 years ago, some whites still think of blacks as inferior -- or as children.