Someone Explain the Joke Rules to Me?

Once again the liberal blogs have picked up a story running through the social media. It appears they are rather up in arms over this photo:

Here on the far right we have Greg Cimeno - who I also happen to be friends with on Facebook, and have been for a number of years. I don't know him personally but I do feel as though I know him. We've chatted rather frequently through the years and I consider him to be a great guy. He's young, very ambitious, and has always been an open and honest guy as far as I can tell.