Why does iago refer to othello, not by name, but by words of which reflect his race?

Othello is a "moor" or black man. Although Othello is militarily indispensable to the monarchy, he is still black. Iago hates Othello because Iago was not promoted. Much of his hate is projected through the filter of racism. Although racism towards Othello was not overt, it still existed amongst most of the white population.