Mexico is a nation, not a tribe or a particular race and only about 1 in 5 residence of Mexico identify as indigenous.
The La Raza racist ideology is that Mexicans are “indigenous” people of the Soutwest and California, like Indians, and are entitled to special racial and legal status because of that.
It is not pure happenstance that Cortes took only 500 Spanish soldiers to conquer the great Aztec Empire. He got a lot of help from the remnants of the tribes which they enslaved or slaughtered.
It is also likely that at least some of the Navajo, Hopi, Zuni, Pima and other southwestern tribes were escapees from the evil Aztec.
I am pretty sure one is not allowed to join groups like “La Raza” until after their divorce with reality has been finalized.