Pixar's films are not different from Disney's, they simply continue the trend he started in his early films. Each of his early films, including Fantasia, which is not anything resembling a children's picture, challenged children to confront fears and realities of life. Yes they included many pieces of saccharine characters and happy endings, but they also can be terribly frightening, forcing children to confront their fears of lying, separation, and death. These were no Mickey Mouse or Silly Symphony cartoons.

Toy Story 2 and Finding Nemo essentially channelled Pinocchio in exploring separation and growing up. Only the masterpieces Ratatouille and Wall-E have entered a different realm, because the company has been successful enough to allow greater artistic expression. Disney never had this opportunity: his studio was taken over for the war effort, and Disney lost so much money he wasn't able to experiment more until the mid-1950s, at which point he was much more involved in his Disneyland than his animated films.

Let's put it this way: if Disney's early films were all "naive" pieces of art, then I suppose the young Bambi's realization of every child's worst nightmare- the death of his mother- was somehow intended to delight children.