This comparison is apples to oranges. Intra-EU immigration is mostly high-skilled labor, and the outside low-skilled migration situation is different from America's. In America, most illegal immigrants work in huge numbers in the service and agricultural industries. In Europe, the most comparable group of people being migrants from Africa and the Middle East, are overwhelmingly unemployed. There's less of a supply shock to labor, but certainly very large costs to the state and its healthcare programs. Many European healthcare systems are more strained than ever.