I've seen people who demand a more socialistic society that still have a slight grudge against Latinos. One of my close friends is one of them. He's a huge supporter of free education and disintegration of the big corporations, but still believes "those damn Mexicans" should "stay in their country" and "solve their own problems". A lot of people believe that because they support a "liberal" agenda that they're automatically open-minded and in support of a more equal and fair reality. Unfortunately, the fact that they make such an assumption to begin with usually means they don't fully understand what liberal thinking is, where it came from and why. In tandem, most don't understand what conservatism really is and why, either.
So, in a nutshell (and like you say), I haven't seen droves and droves of people who think this way, but I've seen (and listened to) enough that I felt it "humorously appropriate" to generate this meme. ;) It's my way of pointing out how a lot of humans only think things halfway through.