Ever since I saw this special, I have had many scenes in my mind for G.I. Joe.
In this MotU special, "Christmas" was cast as a metaphysical threat to authoritarian control, Horde Prime's control, a threat to his Horde Empire. The children from Earth, on Eternia, were carriers of a belief system that destabilized the villain's power structure.
Skeletor, long-time villain of He-Man's cartoon, and Hordak, the lead villain of She-Ra's toon, were summoned before Horde Prime, the most powerful and evil being in all the universe. Both villains were rivals, yes, and hated one another, certainly. But under Horde Prime's gaze, even their egos shrank.
Horde Prime believed that the Christmas spirit was a threat to his power. He ordered them to capture the two Earth children, saying that whoever brought them to him would be well-rewarded.