"They would rather loose a ton of food and not fill orders than pay more per hour for a worker?"
At a fairly low point, increasing the cost of the labor removes all profit from the equation, and it becomes cheaper to simply let the produce rot in the fields.
Unless, of course, you're willing to pay a lot more for lettuce. Maybe you are. I might be. But is everyone ELSE willing to get hosed for this?
It's just like paying for gas. It's called supply and demand all around.
So as long as it keeps the prices low, it is alright to break the law?