In general, people ought to be kept in the places they fu??ed-up. Fu??er-uppers are seldom assets where they go, but might be useful straightening things up where they came from. If they stay home and improve things, that is good. If they stay home and get waxed, that is perhaps unfortunate. If they emigrate and screw up the country that receives them, that is bad. If they wax citizens of the country that receives them, or upset its culture, that is bad.
If we let people in who are from defective civilizations, we are stupid. Just say no.
Since the left changed the immigration laws 45 years ago, the west is in a state of being colonized, broken up, erased, and replaced with new countries that will only retain flavors and traces of the originals.