Just as union extortion causes artificially high wages, Mexican illegals lead to artificially low wages for the citizen working man. If one builder uses Mexican labor, his competitor also needs to use the Mexican labor to compete. The citizen carpenter is then forced to work at the same wages as the Mexican. I know this by experience.
Note that I am completely opposed to illegal immigration, mostly because it means being overrun by criminals and drug runners. But I fully support legal immigration, so if I had my druthers we would close the borders--but you'd still be competing with the law-abiding cleancut Mexicans that would flood into the country legally.
The cheap mexican labor is also almost entirely unskilled. You can earn more money in construction by: doing skilled work that they can't; moving to a locale where Mexican labor is less available; getting promoted to foreman. But if you're "forced to take the same wages as the Mexican", then presumably you are no more skilled than they; live in Texas; aren't qualified to be foreman. If the illegals work for $2 an hour, you should go to McDonalds where you can make triple that. Or learn to drive a bus/truck/crane, and make 2-6 times the minimum wage. Or become a cop, secretary, store manager or nurses' aide. If you can manage ten months of night nursing classes, you can be an LPN and make anywhere from $20 - $50 an hour.
And I know that by experience. I have a PhD in Mathematics, and was looking for a professor's job in 1996. At that time, famous mathematicians were flooding from Eastern Europe, and wiling to take any pay to teach at any level, including High School. I was indeed unable to secure a job in my field thanks to a flood of legal immigrants. But instead of cursing the @#$@#!$ Russkies, I went into compuer programming, and now make 50-100% more than I would have as a teacher. Cry me a river.