This is a very interesting point. The Absolutely True Diary of a Part-Time Indian is written by Sherman Alexie, himself what Native Americans call a "breed", someone of mixed Native American and white heritage. The novel is quasi-autobiographical, and reflects the realities of growing up on the reservation. The author and the viewpoint character, Junior, are both, at times, scathingly critical of the reservation society, especially of the endemic violence and alcoholism. Even more profound is the way in which Junior realizes that to get a good education, he must attend a white school, and when he makes that choice, he finds himself condemned as an "apple" (white on the inside, red on the outside).
Since Alexie himself is Native American, and his criticisms are uttered with the passion of one who loves his culture and wants to reform it, I don't think we can call him a racist. Also, even more interestingly, there are many positive portraits of female Native American characters; many of the male characters as well have moments of redemption. The treatment of white characters is quite similar, with his white classmates also including many decent and supportive people, despite many being somewhat racist ideologically. The ending of the novel is especially redemptive, and Junior begins to value both reservation and white cultures, understanding that while both have their flaws, most people as he gets to know them and lets them into his life are "pretty damn amazing."