Heck, there are Hispanic citizens who oppose illegal immigration and also Blacks who oppose it.
The quote came from the movie, Things are Tough All Over, which is a must for all Cheech and Chong fans. It's a scene where they are driving an old pickup truck or some such filled with about 30 Mexicans and the guys' woman-friend turns to the people and says something like, "The reason why this looks so much like Mexico is because it used to be Mexico."
This movie is also notable for the quote, "We are now at the top of the hill and I know where we are. We are in the middle of fucking nowhere!" (I'm trying to find some YouTube clips for all of this but so far no luck.)
http://www.youtube.com/watch?v=oeCDnCcwfwU
The problem is not immigrants as people, the problem is with the numbers of immigrants. See:
http://video.google.com/videoplay?docid=5871651411393887069#