That's simple minded, mean, and just not true. There is NO place where that is the case. There are many places, even in the US, where people don't get a chance to develop intellectual skills, but given a chance we do see great mathematicians coming from India, Africa, South America, actually there is no population anywhere on Earth that is statistically less intelligent especially when it comes to surviving and developing skills to survive. I would have died an early death in many parts of the globe unless I learned how to survive there.
The problem you have is that many of these refugees are smarter than you are because they survived an epic journey and they become a successes when given the opportunity while your tired "sophisticated" genome is about to become extinct, and that has you scared.