Because it is, always, every time it's brought up, every time it's stated. Sometimes people are clever and hide their racism in a few layers of "look at this lazy white person! I don't like him either!" but dig for a minute or so and you'll always find the truth. Occasionally it can be about other minorities, which you are correct to point out -- Hispanic Americans, etc.

But my two hypothetical quotes were simply examples of the attitude that is so common, not explicitly trying to accurately characterize the parent or GP.