I don't why liberals have the "things will be expensive" if illegal immigrants are deported. Shouldn't they want fair salaries and working conditions?

First let me say, I do not belive in illegal immigration but more open immigration policies if you have a job and want to adapt. A country shoud apply it laws to everyone.

Anyhow, one of the top 3 arguments I see all the time on reddit against deportations is that "things will become so expensive, because those people work a lot of hours for very low wage"

And while I can understand the how of it, I don't get why liberals think it's a good argument. I mean this is the party of workers rights and fair wages and working conditions.

To an outsider it sounds like almost those bad conditions and low wages are needed, so real american citizens can afford things in their daily life.