We the people of the United States of America. Not "people of the world" or "people of Mexico and the United States". No sane group creates a constitution for people they aren't even a member of.
The idea is that you come here, become a citizen, and meld into our culture. Recently, leftists have decided that America shouldn't expect those who come here to adhere to our rules and traditions. Part of being a country is to have commonality, something that defines us and brings us together. Leftists like yourself like to keep us separated and at each other's throats.