There's another difference: most Arab immigrants to the US are Christians fleeing the jihad.
Actually, they're not. We have a very generous policy for ME immigrants. We cut back after 9/11, but now the Saudis and other ME folk have obviously worked their magic, and we are letting in lots of non-Christian ME people, either on temporary visas (which of course they will overstay) or on a family reunion basis. I'm not worried about Mexicans; I'm really worried about Muslims, but nobody seems to care about restricting their immigration to the US.
Plus, of course, Muslims come backed by Saudi money. I was in Houston last week and saw that the "Islamic Dawa [Conversion] Center" has bought an old courthouse downtown next to the new TX State Court.