Thinking back over the past decade, it seems that the peak of anti-immigration madness was one of those luxury concerns, something people could get upset about when there weren't real problems to worry about. I don't doubt that the 27 percenters are still capable of being incensed about it, but as a national issue it just doesn't have the resonance that it did a few years back.
It's also one of those issues that just breaks the brains of so many people, as any immigrant is experience is so, well, foreign to them. So few people have actually lived in another country, or even visited for an extended period.