rud tud is a dirogitory term used for anyone of a race that is not your own. It is a way of calling someone not only stupid for the color of their skin but also reminding them ever so frivevelantly thay they are lesser then you and your kind.
Generic White Racist Man: "YO check that stupid ass rud tud"
Generic White friends: "yeh yeh! rud tud, rud tud"