It also strikes me as a somewhat fatalistic and faithless attitude to believe that a small minority of people REFUSING (it's funny how these xenophobic arguments seem to reappear occasionally, isn't it?) to learn English and/or "using our system" to enrich Puerto Champerico will somehow overwhelm our economy and destroy the country.
See the thing is, they're "using our system" the same way we're "using them". When you work, you're performing a service. Someone is making money off you working, whether it's the company you work for, or you yourself. So these people working, is making someone else money. It's not destroying the economy, it's helping it. It's money that without them, the economy wouldn't have. The fact that they're sending their pay checks to their home country doesn't help the economy, sure. But it doesn't hurt it either. It's a cycle.