Although I agree with you, that part of the episode doesn't bother me so much mainly because it is a very common trope in TV and movies, the mentally ill character who is on medication and everyone writes off as "crazy" is the one who is actually in tune of what's going on, knows the truth of the matter and ends up saving the day much to the chagrin to everyone. The moral of the story is supposed to be a cautionary tale about ignoring people you really shouldn't ignore, but unfortunately it really doesn't take into account that most people on mental health medication really need to be, and just tossing away their pills will cause problems rather than solving them.A kids / family television show airing an episode with the message that going off your mental health medications can save the world is not only irresponsible but reprehensible.
Although your post has me wondering, how many children on mental health medication felt a need to stop taking their medication after seeing this episode so they could talk to the fairies. Now that's disturbing.