And in the novel (series) the warning is that overindulging in escapist fantasy is a toxic and self destructive behavior that stunts personal growth as children obsess over fiction and grow into adults that ignore the real world in favor of picturing themselves as the protagonist at the center of everything.

Bastion goes from boy hero to betraying Atreyu as he tries to rewrite the story into making himself supreme ruler.

So, obviously the movie makers stripped out all that trash that doesn't apply to modern life.