That is a big part of it, but they also don’t mind their peasant class coming up here and getting all the freebies they can (off of our backs) so they don’t have to fund feeding & educating them either.
Mexico is an aristocratic society. I lived there for close to a decade. Nobody cares about the indians.
The aristocratic government went out of its way to open consulates in every large city in the USA and to issue citizens ID cards to any Mexican who asked. So, they are Mexican citizens of record and can actually prove it.
We need some conservative immigration law firm to offer to represent these Mexican citizens within Mexico so they can reclaim their citizenship.
As an added inducement, we own a few desolate islands and atolls in the Pacific. We could offer to emulate the Aussies and relocate all illegals to one of those. Let the UN provide humanitarian assistance. It will become a hellhole, attracting all the Chardonnay socialists and big mouths, conveniently distracting them from other seditious endeavors. When we receive the inevitable condemnations, we could point out that these are Mexican citizens being denied their rights to live in the land of their heritage and birth. We’ll even provide air transport in military cargo carriers.