"Do racist think that because they are white, they are superior? "
One doesnothave to be white to be a racist. Racism can be identified anywhere in the world. it is when one group appears different from the other in skin color, culture, class or national origin, discrimination often occurs against the other group, most often based in myth and misinformation.
Without intervention this prejudice turns hateful, each group no longer relates to each other as human beings, but something sub-human.