I'd rather let my daughter watch SpongeBob or Octonauts or Ghibli movies rather than shows that tell her that every aspect of her self worth should be defined by how useful she is to the rich people in town.

And that's the underlying justification for a lot of the episodes: Thomas has an obligation to be grateful for his work and to do as he's told. Even when he doesn't like the job. Even if there are better things for him to do. Even if his friends are sad or in danger.

It's a pretty vile lesson.