Given my beliefs, I am often accused of being an "open borders" type. And I admit there is some truth to that. I believe we need a combination of enforcement, amnesty and a guest worker program to solve what right now is a huge problem.
But it strikes me that people are opposed to "immigrants" as a concept. Everyone knows immigrants and even the most intractable anti-immigration person can point to an immigrant they either work with, or friendly with or hire for some job. The problem is not the immigrant we know, but those we do not. The nameless, faceless throngs you see at job sites and around town or maybe just read about. A family of five immigrants living down the block from you is not scary. 12 million illegal immigrants are.