The term "learning disability" has appeal because it implies a specific neurological condition for which no one can be held particularly responsible, and yet it escapes the stigma of mental retardation. There is no implication of neglect, emotional disturbance, or improper training or education, nor does it imply a lack of motivation on the part of the child. For these cosmetic reasons, it is a rather nice term to have around.
U. S. Government Study On The Labeling Of Children