I've yet to hear a compelling argument to the contrary.
You apparently don't understand the process of the Drug dealers addicting people.
True, we have had the problem for years but not the violence that we are seeing now. Right now the killings in Mexico are related to drug gangs claiming territory for the US market.
By the way, right after 9/11 the Mexicans got behind on shipments north as the borders were somewhat closed. That didn't last for long.
So as far as I am concerned the argument goes as to which came first "the chicken or the egg".
Similarly, if American jobs, schools, hospital facilities and other handouts weren't so damned attractive to illegal aliens, there wouldn't be any Mexicans in this country illegally...
Same stupid reasoning to excuse the inexcusable.