Why is Mexico so racist against Native Americans?

Two reasons. From a practical point of view, Mexico would like to advance its economy out of the third world and the ruling cl feels that traditionalist are holding them back. The other reason is that the ruling cl most identifies with an Aztec heritage, and Mayans and others in Southern Mexico are tradtional rivals. So there is not much concern when they fall behind. This I heard from my Mayan tour guide while I was visiting Mayan ruins in Mexico. He had a constant commentary about U.S. Imperialism in the middle east and Aztec imperialism in mexico. When i asked him he said he was referring to the people in control up in Mexico City (formerly the capital of the Aztecs). I know that is not an academically verified source, just what a local told me.