"There is no shortage of American workers. Just a shortage of American workers who want to work for an obscenely low wage."
Well, uh, duh. LOL. If Mexicans are willing to work for the lower wages, so be it. Let them do it.
I don't have the time tonight to point out all the ways in which your comment is harmful to the country, so i'll try to keep it brief.
What you have proposed keeps both the standard of living AND wages artificially for certain classes American Citizens. This takes what might be reasonably paying jobs away from Americans, because were we to disallow illegal people from working, wages would have to reach stasis with the job market before anyone would perform them. This is a good thing. It is called the "free market".
The free market doesn't work when certain industries are allowed to skirt (as in outsourcing jobs to Malaysia), oroutright break the law (as in hiring illegal Mexicans).
The gentleman who builds homes was a perfect example. He cannot hire American workers if he wishes to compete.
I don't see how that can be good for the American worker.