Ironic.
Mel Ferrer, who plays a racist in this movie, also played a light skinned black man in "In Lost Boundaries" (1949) who, along with the rest of his family, are passing for white. Casting white actors, in such roles, was the norm during the thirties, forties and fifties, but it's still ironic.
TAG LINE: True genius is a beautiful thing, but ignorance is ugly to the bone.