The issue is that, like many things Trump has said, mixed signals are being sent. He railed against the diversity visa lottery because it allotted immigration slots based on nationality, not merit. Then he rails against allowing immigration from "shithole" countries and says he wants more European immigrants, without mention of any merit or qualification. He didn't say "we need more doctors/engineers/scientists," he said "people from Norway."

If you want to have a merit based immigration system, it has to be color-blind. A doctor from Sudan and a doctor from Norway should be treated equally, assuming both are sufficiently qualified. A Haitian engineer should be more likely to get papers than a German truck driver. By suggesting that some nation's immigrants are more desirable than others purely based on their nationality, he undermines his own push for merit-based immigration.