This is a very wrong misconception. Mexico is made up of different colors, the white, green or blued eyed european blood is still very much alive in Mexico. There is even some black Mexicans and a small amount of asians.
He was effective until he got caught/tagged. Canelo's defense looked **** tonight, let's not paint it any other way. He just happened to be in there with a guy who was even worse, who he knocked two shades of **** out of in the first round and never let recover.