What happened to Spain on account of the mix and the only place in Europe with higher learning eventually lead to the Enlightenment and the Renaissance. It's not exactly coincidental or accidental that after the purge via the Inquisition, once the flood of stolen commodities from colonies abroad ended, Spain's leadership culturally and technologically slipped to the lower rungs of Europe. Once they got rid of the brains, they got rid of the brains.
Meanwhile, on the other side of the Atlantic, mixing of peoples and an abundance of resources lead to a blossoming. If you think the EU is just being all altruistic, you are an even begger idiot than you pretend to be. They are trying to replicate the American formula - spurring innovation and growth by adding new blood, as well as gaining a growing market (many EU countries having negative native growth rates due to dropping birth rates) and cheap labor offered by the less skilled.
Also, less homogeneous populations causes people to be less unified and more selfish, again, spurring growth as well as making them easier to control in a divide and conquer sort of way.
The problem with cuckold gimps like yourself is that you're so hyped up on your hateful idiotic propaganda that you never stop to consider that you might actually be on to something. Yes, they want people to be uncomfortable and paranoid and antagonistic against each other so they can be distracted by their hate for each other, while the powers that be sit back and enjoy the minions be dutiful little consumer drones yapping at their neighbors rather than their controllers.
