I'm not sure why anyone would assume that because Gibson is a staunch Catholic he would be supportive of everything George W. Bush does. It's kind of weird how all Christians get lumped into one big belief system-hey, Mel likes Jesus, he must like George Bush too, right?
The Catholic church is pacifist and opposed to the war in Iraq. Not surprised to hear that Gibson may be as well.
Correction, the Catholic Church is not pacifist, it does recognize "just wars" and the ability to defend oneself from harm.