I gave George W. Bush a lot of credit for one thing. After 9/11, he really did make an effort - and did a pretty good job of - diminishing anti-Muslim sentiment. The narrative of Afghanistan was that it was a country of good people ruled by bad people, and we needed to take out the bad people both for our sake and for theirs. This is all cartoonish stuff, but such are narratives. And then Iraq. Peeance, freeance... and then those ungrateful Iraqis started to fight back. Why? I don't know. Ask them (people rarely did). The narrative for staying in Iraq, and staying in Iraq, and staying in Iraq, required it to be filled with bad people. So "they" (Muslim-ish people from the Middle Eastern-ish part of the world) all became bad again.
While the refugee response discourse has mostly been focused on Europe, because they're where they are coming to at the moment, America "can't" and certainly won't take them in. They're all terrorists, after all.