I don't know if I'd go that far, but I think it's irresponsible. Someone on another thread said he's taking his 6 yr old daughter this weekend (based on seeing it already). I don't care how "mature" or well-schooled in the gospel, no child that age should be watching this film.
Roger Ebert's review said that if it had been anyone besides Jesus depicted on that cross, it would have unquestionably been rated NC-17.
I imagine that the film will bring out the best and the worst in people, much like this thread has done.