Why upbraid them? Anyone who assumed Mel made a movie about Jesus Christ also meant he was a Republican and Bush supporter should upbraid themselves. Mel may have made some great movies, even ones about freedom and Christianity. But you should never assume anyone believes a particular way, especially in politics, when it comes to anyone associated with Hollywood.
On the other hand, like I just posted, you can disagree with Bush and still support him. Who knows for sure who Mel supports or what he believes. Maybe he's throwing a bone to Hollywood to get back in their good graces. In the end, does it matter anyway?
Conservatives have seen the movie, time to get the liberals' dollars.