I think the main issue here is that children, at such an impressionable young age, find it much more difficult than adults to distinguish between fantasy and reality.
Yes, it is a worthwhile and praiseworthy effort to try to provide Jewish kids with good, clean entertainment (G-d knows how bad the Disney and Pixar movies have gotten lately). However, if it means that our children come away with a misconstrued idea of how the Purim story happened, or even worse, come away thinking that the Purim story is just as much a fiction as a Disney story, then that's a huge problem.