Of course they are. Why else would you oppose immigration, except to be able to exploit illegal immigrants?
By virtue of being here unlawfully, they have little recourse. That fact alone is essentially leverage for any “employer” to exploit them over.
It’s clearly not because they are a drain on the system, because that’s been disproven time and time again. Their economic contributions far outweigh whatever little social programs they’re able to obtain.
So it must be because they are a great pool of cheap, under-the-table, sub-minimum-wage, exploitable labor. Just like prisoners and prostitutes (except for the sans sub-minimum wage part. Plenty of illicit sex workers that are unpaid victims of trafficking, but if the John is paying less than $7.25 an hour, they should really know better)