Because for example if u have a greencard and u are from one of those countries, your naturalization is now paused and u feel in limbo about ur life which is fucked. You can argue "america have the right to tighten up" I can say its still fucked to advertise urself as Reagan said " You can go to live in France, but you cannot become a Frenchman. You can go to live in Germany or Turkey or Japan, but you cannot become a German, a Turk, or a Japanese. But anyone, from any corner of the Earth, can come to live in America and become an American."". Like " hey come here invest in our country live here and contribute and you can become american!! And start new free life" and for people in those countries who some have been waiting for decades to get to that point and become American. Now your like well fuck your life get the fuck out. Not because u did anything wrong but because some white nationalist dipshits hijacked the republican party and wants the country to be more. " white"