REBUTTAL: Many American Indians don't like a day heralding the "discoverer" of their land. . . . "Columbus Day is an abuse of our sensitivity, and we should just forget it. It brings up too much emotion," says Little Crow, a Sioux who heads Garden Grove's American Indian Unity Church. Bowers Museum curator Paul Apodaca, a Navajo, would like to see Columbus Day replaced by American Day, to recognize contributions made to the world by American Indian culture. . . . As for Norwegians, they'll celebrate Leif Ericson Day on Wednesday to honor the Norseman who may have landed on the continent 490 years before Christopher Columbus.