The sad thing is, the more likely “fix” for this will just be legalizing this insane system of unfairly and illegally-paid migrant workers rather than forcing the ag businesses to offer fair compensation.

Or they'll use prisoners.

Would it even be America without a non-citizen underclass to do all the hard work while their free existence in society is made illegal, justifying oppressive police forces to "deal with the problem"

Legalizing immigrants means they can't get deported for fighting back or trying to quit. And having no choice is the #1 requirement for exploitation.

Yes.

This is all easily predictable if you aren't in an un-reality bubble.

Yup. Surprise surprise, if you exit the EU you're not going to get business from a lot of truck drivers that live in other countries.

The Brexit leopard ate their Brexit faces.