Citation needed.
All the 20th Century Latin American flirting with Socialism and Communism combined with a cultural tolerance for corruption created that environment. The US is under no moral obligation to accept anyone that shows up at our border with a claim that they are fleeing a country not as good as ours.
In fact if I recall correctly, the international standard is "first free country", not "whatever country I want".
My mother was an actual refugee in WW2, and I still recall her story of the choice of either going barefoot, or taking the boots off one of the bloated dead guys on the side of the road, as everyone in their group had to do.
The "refugees" that show up at our border wear Nikes, logo t-shirt, and more often than not, have a phone in one hand and a bag from the Burger King in Ciudad Juarez in the other. Because Mexico has a thriving economy and large middle class with suburbs and everything, and that's where the "refugees" should have stopped.