Look, the demand for a free service is infinite. For an expensive service like medical care, giving it away is very expensive indeed.
> Forgoing your blatant racism, ...
"Racism" is not a general purpose swear word, any more than is fascism. And even if my motives were naked bigotry, Mexican is a political affiliation, not a race. The appropriate accusation would be to call me an American nationalist.
> Switzerland, Australia, Canada, New Zealand, and Austria all have higher immigrant percentages than the US ...
Their immigrants are heavily skewed towards the First World, and screened for acceptability. None of them share a border with a famously corrupt third-world country. (I suppose Canada may quibble. ;-)
If you actually want to learn about the Latino medical theft problem, do some reading:
http://www.nytimes.com/2009/11/21/health/policy/21grady.html...
http://www.cairco.org/econ/econ.html
http://www.newswithviews.com/DeWeese/tom94.htm