We invaded their land. We did it on the basis of Bush’s lies that Bush had conclusive evidence that Saddam was six months from a nuclear weapon and had been behind the 9/11 attacks. He blatantly misrepresented the evidence that he did have. And instead of Bush, or any of his successors, apologizing for this — the destruction of Iraq (on the basis of lies) — there has been continued military occupation of Iraq, and forcing of its Government to do what our lying Government demands, such as privatizing the oil and paying international oil companies to exploit and market it — their oil.
The reason why “they feel they’ve been betrayed” by Trump’s bar against any Iraqi relocating to America is that many of these Iraqis had been hired by U.S. firms to do translating or other essential assistance to the invaders, and so they are themselves now hated by the locals, their own countrymen, and they think that the only safety for them and their families would be to move, along with their families, to America. They are therefore now terrified, at finding themselves stranded in Iraq, where they are very reasonably considered to be traitors.