Ever since the 17th century, America has a pro-immigration tradition that few other countries share. Palestinians in Egypt would look and sound like foreigners, and the Egyptians would not like that – remember that Egypt made a point of not annexing Gaza when they had a choice.
America has long accepted “huddled masses, yearning to be free” (which is the case of those trying to come in now), and indeed, in the last presidential election neither party nominated a candidate who ancestors were living in the United States at the time of the Revolution (something that never happened before); in fact in America, most of the “nativists” are themselves descendants of recent immigrants.