The entire point of our existing system is to guarantee the perpetual presence of a large population of hard workers with absolutely no legal rights in the labor pool.

If any complaint means you and your family might be immediately deported, you’re not going to ask for a raise (or most government services), and you sure as hell aren’t going to try to form a union. Employers haven’t figured out how to put all workers on that position yet, but it’s not for lack of trying. They get the benefit of a side effect that legal workers are always afraid their job will be outsourced to immigrants, so they too are leery of asserting their rights.

Whipping up anti immigrant sentiment actually helps perpetuate this system, since it lets you put all the heat on the workers and ignore the role of the employers. And just “getting tough on immigrants” (aka giving government more freedom to gratuitously abuse brown people) will never happen, because it would destroy entire industries, as we find out every time some southern state passes, then almost immediately repeals, this type of law.

Actually penalizing employers would require the labor markets to change in ways the Republicans would hate (fair compensation and rights for workers is anathema to them), and the Democrats don’t seem to care enough about to fight for. Probably because of their longterm shift towards dependence on corporate donors. Honestly, unions should be at the forefront of trying to fix this, but they are not very strong these days, and blaming immigrants is always easier than finding good solutions.

TL;DR Working as intended.