The sources tend to indicate that his being African-American, and the fact of his being the first, are of great (one could say monumental) importance in American politics.  It's not really a question of whether one agrees or not.  In a perfect world it would not be a big deal, and people would see him simply as the President... or could mention race as an interesting cultural characteristic like being left-handed or a basketball fan.  But the world is not perfect, and his being the first black president of America represents a historical shift in race relations.  Perhaps ten years from now societal mores will change and it will not figure so prominently.  Wikipedia as an encyclopedia is a product of its times, and inasmuch as it draws on sources with cultural biases, it is a product of the various cultures that produce the sources it cites.  It's not practical to try to achieve objectivity through logical analysis - that's also a form of bias.