Interesting story my uncle told me about an acquaintance of his, guy that owned a construction company. He'd go round up a bunch of illegals and offer them work. Deal was that they'd stay in a house he owned, eat the food he provided (cans of beans and packages of tortillas basically), and once the job was completed he'd pay them out of the money from that. So these guys would put in weeks of construction work and, when the job was just almost completed, this guy would call immigration on them and get them deported. He'd bring in another crew, pay them for like two days of work max, and then start the whole process over again. Sometimes he'd even pick up the same guys. "Hey, you know what the arrangement was, and you didn't finish the job. Don't worry, you'll get paid this time." Effectively everyone gets shafted... the illegals get shafted out of everything but basic room and board for two months, the professionals only get paid for two days instead of two months.
Now, one person hears that and their thought is "Maybe if we stopped illegal immigration, guys like that would have to give up their shitty schemes and actually pay their legal workers a decent wage."
Another person hears that and thinks "That's terrible! He shouldn't be able to treat his slaves like that! We should get rid of the immigration authorities!"