In Pan’s Labyrinth (El Laberinto del Fauno), the new film from Mexican-born director Guillermo del Toro, fairy tales are terrifying. This is how fairy tales are supposed to be: coded ways of telling children about the harsh realities of adult life. As the goal of American parenting has become shielding children from reality, as if it did not exist, fairy tales have in turn become been watered down and made less frightening. In the case…