The guy is on a whirl wind tour of the country, from early morning shows to late night shows, he may not be keeping up with current events right now.
With respect, think about what you just wrote. When you're trying to climb your way out of a public relations hole, rehabilitate your career and promote your new movie, as Gibson is, via a whirlwind tour of interviews, you don't necessarily need to keep abreast of everything that's going on in the world, but you'd darn-well better be prepared for questions related to your particular PR "problem". To not do so is just plain foolish.
This isn't rocket science. Here's how it's supposed to work:
INTERVIEWER: "Mel, what do you think about the recent Holocaust Denial Conference held in Iran?"
GIBSON: "When I heard about it I was shocked. I think it's shameful. One of the lessons I tried to convey in my movie 'Apocalypto' is that we need to remember, and learn from the barbaric realities of history."
See? Simple, effective, and it quickly deals with and disposes of the potentially embarrassing issue. Sadly, the fact that Gibson can't bring himself to do these simple things is a telling indicator of deeper problems.