BS. They are one and the same.
There is a historical pattern of migration of Mexicans into the US just as there is a pattern of migration within the US. People from the NE go to FL and people from the midwest go to Texas.
Mexico is not one homogenius group of people. Do you know about the big people and the little people of Mexico? Those from the south versus the north? Can you comprehend the effects of "Operation Wetback" in that it birthed the maquilladoras which exposed northern Mexico to capitalism? Recall that when the reformers left the PRI they went to the PAN because it was the party of the "hard charging capitalists" of the Mexican north.