Your working conditions and salary would be substantially higher if those people weren’t in the country to begin with.
But they are in fact full-fledged human beings living physically in the United States. They are buying groceries, paying rent, getting their haircut.
Once you realize they are fully participating economic actors, it is much less clear whether they are a net positive or negative.
As if your (very American) bosses wouldn't find another to put you down and wrong everything they could from you. Today ICE is going after immigrants, tomorrow Pinkerton is going after you.