In the movie, Rainbow Brite and Krys, young children, are chased by monsters that want to eat them.
The Dark Princess and the lengths she'll go to to get what she wants can be pretty scary. When the source of her power is finally destroyed, she tries to ram into Spectra with her spaceship, in the hopes of destroying it and any hope of the universe's recovery.
The movie opens with her being told that stealing Spectra could destroy the universe. She doesn't care.
One episode of the show has Murky capturing and torturing Moonglo with bright lights. In the same episode, he nearly kills Rainbow Brite by pushing her into a pit.
It's mentioned on the Humans Are Cthulhu page that colorizing the setting is Hostile Terraforming for no other reason than the group of kids don't like the way it looks; similar to an alien species gassing a city of earth with, say, chlorine because they like the scent.