One thing Fox refuses to confront is the rampant corruption at all levels of government in Mexico. There is a reason why they use Mexican Marines to do the high level enforcement. Everybody else is assumed to be corrupt.
One thing many Americans, even American conservatives, refused to confront is the increasing corruption at all levels of government in the United States as a result of the failed war on drugs. At the very least, the failed war on drugs has infringed our liberties, our privacy, our expectations of due process, and our economic well-being.
So long as the United States persists in fighting a war that is clearly lost, building Trump's wall might have some marginal utility in that war effort. But wall or no wall, it must be understood that the more we succeed in fighting the war on drugs the more we lose because interdiction of the supply of drugs drives up the price in an inelastic demand market and therefore increases the incentives to smuggle the drugs in. The price of heroin in Virginia where I am today is remarkably cheap, indicating that there has been very little effectiveness in attempts to interdict that drug.
Meanwhile, our war on drugs has made it lucrative to raise poppies in Afghanistan thus putting the United States in the anomalous position of funding our own enemy in a war. Vincente Fox has it right, it is American demand that makes the corruption in Mexico profitable and possible.
It does no good to blame the messenger, so long as we persists in waging our war on drugs we will continue to lose that war, we will corrupt our criminal justice system, we will continue to addict every new generation, we will fund our enemies, we will impoverish ourselves.