Migration of people from Latin America

when the national conversation about the migration of people from Latin American countries to the US talks in terms of an ‘invasion’ of ‘illegal aliens’ that threatens the survival of ‘our values, freedom, and way of life’, what are we really talking about here? Looking at the history of things, is there maybe some dark irony in this sort of rhetoric?

Also include other examples from other Latin American countries as well not just Puerto Rico which is attached.