It might be region dependent then. In my neck of the woods foreign workers are specifically brought in to work the minimum wage jobs that no local would work for the low pay and bad treatment. They're really taken advantage of as their ability to stay in the country is tied to their employer (often their employer is even their landlord too) and it's all on the books and legal, but suppresses wages while also raising demand so prices go up despite the stagnating wages.

I guess we may be talking about different things as temporary foreign workers aren't technically immigrants? It's meant to be temporary I guess, but even if they don't get their permanent residency if they're swapped out for a new person to abuse the effect is the same or worse.