Matthew is a racist because:
He sees the President first as a black man and then as the president. As such, any disagreement is because he is a black man. If he saw him as a president first, with his own ideas and policies, (like most people on the right that i know do) he could then see it has nothing to do with his race. But in Matthew's mind Obama is black above everything else and he just can't see past that.
But then I live in a real community where we have all races working, socializing, agonizing, teaching, learning, dating, marrying and worshipping along side each other.... a way of life totally foreign to Chris Matthews.