Why are native americans not considered aztecs/mexicans.?

Just wondering why native americans are not considered mexicans/ aztecs. it seems to me that all life around the world seems to stem from the building of megalphyic structures. the cradle of life in the americas are the pyramids of the aztecs and mayas. now i know people like to say they crossed some land bridge from russia through alaska all the way down, but come on that sounds more far fetched than a pig flying. come on you really mean to tell me pre stone age people crossed thousands of miles of harsh living terrain on foot. mountains and snow. then kept walking all the way thorugh present day canada and the united states to settle in mexico. that would be pointless. youd think once they got out of the blizzard like conditions theyd be like lets just stop, but no they decide to walk across a desert too. are people really this stupid to believe that or am i just crazy. well im not crazy and anyone with half a brain and a outside the box mind could see life in the americas stemmed from present day mexico. the people we call native americans were just aztec mayans who decided that the gr would be greener elsewhere. the white man was the man who named them. they were all just different tribes of rogue aztec mayas. the white man was the one who mapped out the countries, hahaha ur mexicans now your peurto ricans and you are cubans . utterly ridiculous.