The Congresswomen in question are AOC, Ayanna Pressley, Ilhan Omar and Rashida Tlaib. "Go back to where you came from" is of course one of the oldest racist tropes in the book, and makes no sense through any other lens, as 3 of the 4 Congresswomen were born in America, with Omar immigrating legally and gaining full citizenship.
This is an explicit white nationalist argument and uses the concept the Germans called herrenvolk - only the dominant ethnic group is entitled to run the government, and representation and empowerment of others is illegitimate. Note the direct contrast between these American citizens and "the people of the United States" and "our government". It's not just couched as political disagreement, it's literally saying they aren't really Americans. Blood and soil, as the Charlottesville marchers chanted.
Time to finally drop the PC crap and the willful obtuseness about the plain and obvious fact Trump is a virulent bigot and racist, as well as the phony argument that the immigration hysteria is "only about illegal immigration". It's about ethnic identity and entitlement, and always has been. This is where we are now. Decide if you're onboard with this or not because it's not going to die when Trump leaves office.