People in those countries vote, as JFK phrased it, with their feet. U.S. immigration categories for the highly skilled (including scientists) and others as well, are filled to overflowing. This means people from that part of the world often must wait for many years before securing permanent resident status. Of course they may be unaware of the looming ID threat to their professions, but most are too busy trying to get here, to stop and read that propaganda.