Movie-maker OLIVER STONE has blasted media groups who "slander" celebrities for their political comments - because intelligent stars have every right to question their leaders. The Vietnam veteran, who is a fierce opponent of the US leadership, is appalled every time a celebrity is rudely mocked for making his or her thoughts about PRESIDENT GEORGE W BUSH and the war in Iraq public, and he urges journalists to be more supportive. The NATURAL BORN KILLERS director says, "We're Hollywood wackos and all that stuff, left-wing... (It's) an easy and facile dismissal. "I'm still a citizen, I've served my country as...