WorldNetDaily: Doctored Dean photo pushed GOP candidate

I usually don't read World Net Daily, but after hearing something on the Randi Rhodes show, I had to hunt this (Doctored Dean photo pushed GOP candidate) down. The actual photos can be seen here. The scary part about this is that a Republican would be okay with this kind of outright lie. The game was up when a young woman recognized the people in the background and knew them to be die-hard Dems who were at a Dean rally. Of course, Bret Schundler claims that he didn't know anything about this personally. I guess I'd believe him on that. Most politicians probably let their web geeks do the real work of setting these things up. They blame the marketing firm, Big Fish, who has worked for both Dean and Schundler. Big Fish reportedly apologized to Shundler, but according to this article, not to Dean or the people in this photo whom they've misrepresented. I'd send Big Fish a message about this, but a "Washington, D.C.-based marketing-communications firm" should have a web site, and according to Google, they don't.
Why do people do silly things like this? What are they trying to hide?