They know that we can't and won't become serfs - the American middle class has all of those pesky, interfering ideas about rule of law, due process, and republican government. That's why we need to be replaced by obedient, docile, and ignorant Third World peasants.
Naturally, the by-product of this is that for every obedient Third World peasant who comes here to mow lawns or push brooms, there's usually a future street thug or gang member in tow, but again, that's not the Koch Brothers' or Mark Zuckerberg's problem - they have their gated compounds and armed private security details to protect them.
BTTT