No ones saying there is something wrong with him being black but there is such thing as reverse racism where people give more to someone because they are a minority, take a look at affirmative action. Jobs should go to the best worker not to the one with the most oppression in their family tree or because they come from a specific country. I think the concern is that people see him as a better president than a white male would be simply because he's the first black man. It's not a racist thing, it's actually the opposite, it's questioning that the reason for giving him the prize isn't racist.