Who, overall, is depicted more favorably in the novel – Indians or white people

I don't think the author tries to favour one or the other. If anything, Alexie has an overriding theme that everybody struggles with the hand they are dealt with. Although white society is favoured and better off, individuals struggle with their own demons. Alexie does, however, devote much of the narrative to the struggle of native people on reserves and the cycle of poverty.