Sure, the homebuilders follow the rules. The thing is, the rules don't apply to illegals.
And what employer wouldn't want employees who work arbitrarily long hours with no overtime, who will work under unpleasant and dangerous conditions and NOT COMPLAIN? And whose existence lowers the wages for everyone else..
What's not to like? Who cares about our culture, language and national security when there's a few more bucks to be made?