The problem isn't that Africans or Central Americans cannot ever be civilized or that there is a civilization gene, the problem is that like domesticating an animal species, civilizing an entire culture is a process that takes hundreds of years. Consider, for example, how long it took the barbarians of Britain and Germany to go from the naked pagan barbarism described by Julius Caesar to the heights of Christian civilization that produced Mozart and the chamber orchestras. The nations of the West doesn't have that much time, especially when they can no longer serve as a strong and stable models, having invited the enervating peoples into their civilizations. Moreover, in addition to attempting to civilize the barbarians inside their borders rather than outside them, they are trying to do so without the benefit of Christianity, which historically played a powerful role in the civilization of the white European barbarians.
… the retreat of civilization cannot continue forever, as history shows the barbarians will simply expand their dysfunctional and parasitical cultures until they are forcibly stopped and turned back. Every civilization needs its Marius, its Qin Shi Huang, its Charles Martel, or will be overrun and die.
Feudalism and the age of aristocracy grew out of a need for protection. It is now becoming increasingly clear why the age of democracy is over and how the coming aristocracy is going to take shape and come to power.