Because it is an assault, an affront, and insult to our spiritual leader, the Vicar of Christ.
Additionally, it is self-serving (see his promotional links at the bottom), inaccurate, and just plain mean.
When somebody takes a shot your pastor, let me know if you will willing stand idly by.
It's happened. There's even a couple of FRoman Catholics here who take regular potshots at Billy Graham and place him in the same category as Al Sharpton and Jeremiah Wright.
Tell the Vicar of Christ to grow a FReeper handle and respond for himself if he's really insulted. He uses Twitter, for crying out loud, so it shouldn't be too hard for him.