This is the most recent argument used by anti-immigration parties. It's probably the most complex argument on this subject, because on the one hand many irregular immigrants end up being employed at inhuman conditions, but on the other hand this fact is usually associated with conspiracy theories and fake news that make confrontation very difficult. Also, you can't blame immigrants for their employers' dishonesty. Although right-wing parties use this fact to support anti-immigration policies, the most active person in the fight against this phenomenon is left-wing activist Aboubakar Soumahoro, who claims that the problem can be solved by promoting integration and education, rather than changing immigration policies.
NGOs funded by George Soros, left wing parties and traffickers are all involved in a huge business that brings them huge amounts of money. They say that they care about human rights, but they are actually involved in the illegal employment of unauthorized immigrants. Those people are then forced to work in brutal conditions. Italy must say no to this by accepting only regular immigrants who can work in proper conditions and integrate.
Left-wing intellectuals and artists have been denouncing the illegal employment of immigrants for years, long before the far-right parties started caring about these issues. This argument doesn't consider that left-wing parties fight for legality and integration too - just in an anti-racist way. The additional theories about Soros and NGOs fail to show a single evidence of their truth.