You didn't read what I read what I posted?
Illegal immigration has always been... illegal. However, those immigration laws and the enforcement thereof was severely relaxed for the purposes of political gain.
Ironically, it was Bush and Reagan that opened that door.
Americans were perfectly fine with new slave labor from immigrants until they started getting uppity, and demanding to be treated like humans. That took several decades (the generation of their children are the more active voices - right on time today.) That is why a creature such as Trump, and an age such as today is perfect for obliterating the political, economic and cultural bridges made between Latin American nations by republicans themselves... like the orouborus politics is.
So, when you ask your question, it begins from a place of choosing to ignore immigration was something politicians and heads of States exploited, and encouraged. They looked away and even took advantage of
illegal immigration.
And, that is ignoring the morality altogether, and looking at the politics. I don't want to go into morality because likely I would have to explain compassion. This generation is too cold to even try and argue from the side of compassion.