United States exists as a country due to the genocide of Native Americans and the theft of their land. It was built off of the labor of enslaved Africans who were never compensated for their appalling treatment or their centuries of free work.
America is also a nation of immigrants who have shaped its culture and transformed it from a racist, bigoted extension of the British empire to the multicultural, largely progressive society you see today. So when Donald Trump argues that the US should not allow immigrants from "shithole" countries like Haiti and other African nations, he is arguing for a return to the nation's white supremacist past. In fact Trump was more specific about this in the leaked report from the Oval Office today -- he specifically wants immigrants from overwhelmingly white European nations like Norway. Via the Huff Post:
“Why are we having all these people from shithole countries come here?” the president reportedly asked lawmakers. He was referring to African nations and Haiti, according to The Washington Post, the first to report the story. It was later confirmed by NBC News, BuzzFeed and CNN.
Trump then said the U.S. “should have more people from places like Norway,” sources told NBC News.
So there you have it, the president of the United States believes black African countries are "shitholes" and their citizens should be banned from coming to the United States, while Norwegians should be given priority because, well, you get the picture.
How much longer Americans put up with this fraudulent racist remains to be seen, but the rest of the world is losing patience fast. White House principal deputy press secretary Raj Shah told CBS News later that “Certain Washington politicians choose to fight for foreign countries, but President Trump will always fight for the American people,” making clear that nativism and rampant xenophobia isn't just a personal belief of the president, but a key policy.