So, where is the source of the problem here? The Mexican workers? They only want to earn money to support themselves and their loved ones just like everyone else working those jobs. So they're not the source of the problem.
The source of the problem is that employers are willing to hire illegally to pay less in wages to increase their bottom line. Capitalism does not explicitly care who gets the wages, it cares about how much those wages effect the profit margin.
I find it interesting how you take the stance you do, but bemoan the basic precepts of the market system that keeps you gainfully employed.