In my reporting, here's what I've learned about immigrant workers (and I mean specifically Latino workers)-
1)They do jobs that most Americans don't want to do, for longer than most Americans are willing to work, for less money than most Americans are willing to take.
2)They are mobile. It is easy for a contractor to hire an immigrant worker, put him on a job in Texas for a month and then move him to Mississippi for three. They often come with their own tents too.
3)Contractors like Latino workers especially because of how infrequently they are organized, i.e. unionized. Sometimes, advocacy groups organize them and demand better pay, but the rate of this is not often.
4)Contractors rave about Latino worker's work ethics. They never call in sick. They work tirelessly. And, many of them have a multitude of construction skills and can therefore do multiple jobs.

All that said, there is no doubt in my mind that local people are not getting hired enough. The reasons for that are surely numerous. One is, I'm sure, the low cost of immigrant labor. The fact is that this country could not survive, this society could not exist the way it does, without the millions of undocumented workers doing our dirty work. The cost to output ratio would be too lopsided without them, and we don't have a system in place to change that right now.
Because of this, and because of the continued threat of immigration authorities, and because of the innumerable unfair laws the government has in place that protect contractors hiring illegal workers but not the illegal workers themselves, the rate of abuse is sickening.
I have heard dozens of stories since the storm started of workers being asked to come here for a job with the promise of housing, working for a week and then literally being left in the street. I've heard stories of workers being promised a paycheck at the end of the day, only to find the contractor threatening to call immigration if they persist in asking for it. The list goes on too.
How do we solve this? I have no frickin' idea. All I know is, it's an interesting and messed up situation.
Our society needs immigrant workers, yet we refuse to treat them fairly. I suppose this system has gone back millenia. The Irish and Italians were treated this way upon their arrival here at the turn of the last century.
Africans are treated this way in Europe today. I suppose it will just be a question of time before Latinos finally infiltrate the upper levels of our society and put a halt to this way of life for their people.