A thought: More Mexicans in Mexico would likely force reform and consumption of its natural resources, weakening oil exports. Under the current system, both Mexican people and Mexican oil go to the US where we make a pretty penny off of both.
In a reformed Mexico US oil interests would take a direct hit, even though Mexico would benefit. I suspect even with pricier oil Americans would also benefit from having a healthier Mexico, but if this guy is right the oil industry has locked out such possibilities.
I think my #48 is a less conspiratorial interpretation of the Mexican oil supply, but it would have many of the same effects and the same interested parties.