I'm hesitant to get into the back and forth all of you have going, but I'd like to answer the, "how is this racist?" question.
Trump, a white guy who leads a country founded and historically dominated by white people, telling a space full of white people (94 percent of Moonship Township's population is white), that a brown immigrant who arrived in the United States as a 12 year-old immigrant and has been a United States citizen for the past 20 years shouldn't tell "us" how to run "our" country. The implication, based on the statement itself as well as in the context of how he has spoken about other non-whites in the past, is that Omar is not really an American. It is very hard not to hear the statement, attach some precedent to it and not hear the racism.
Trump statements in the past about the four democratic congresswomen show he either feels a certain way about non-whites or, at the very least, understands his base does. The first time he told them to go back to their own countries he specifically said all four, but a couple days later amended it to three where it has since stayed. I can only assume that someone he listens to actually told him there was no way to tell a Black woman from Ohio named Pressley to go back to her own country without sounding racist.
Finally, I don't know that Trump doesn't feel the same about white immigrants as he does about non-whites. I just know I don't hear him openly express it.