Can you tell me how all those immigrants "flaunting the law" were affording food and rent, if not for a U.S. citizen paying them for their labor? Why are we not

Can you tell me how all those immigrants "flaunting the law" were affording food and rent, if not for a U.S. citizen paying them for their labor? Why are we not going after those who pay first? Nip the problem in the bud.