We are drifting away from my original claim here, into new claims where I actually mostly agree with you. The original claim was "Illegal immigration hurts low-skilled American workers", and I responded saying "No it doesn't, because those immigrants are taking jobs that wouldn't otherwise be filled, at least in the produce market that presently exists".

Whether people should be willing to may more for their produce, and whether the treatment of these workers is ethically defensible - those are separate questions. I would be totally fine with paying real wages for produce-picking and then subsequently tightening immigration, but there's the paying market we'd like to have and the one we've actually got.