I remember the moment I truly recognized the power Disney has to move young hearts and minds. It was when I attended a sneak preview of Disney’s adaptation of the Chinese legend of Mulan, about a young woman who disguises herself as a man and takes up her wounded father’s sword to defend her nation. I enjoyed the movie, with its combination of swashbuckling, slapstick and show tunes. But as I filed out of the theater, what I saw hit me like a fire-dragon rocket: two blond, apple-cheeked siblings, probably under the age of eight, leaping and sparring and loudly…