This is how the Mexican powerful seek to avoid (more) internal troubles, use that hospitable land to the north as an outlet for all those who seek a better life. No need to clean up Mexican narco-terrorism and kleptocracy, just have that open door to the north.
Mexico is rich in natural resources but has had a very bad history of misgoverning. The remittances from workers in the USofA back to Mexico are a mainstay of their economy. They now have gone from being a good neighbor to being a facilitator of an economic and cultural invasion.
Go north, young hombre.