I think they mean the only other animated Hasbro-based film made in the 1980s (besides, the three you mentioned aren't really family friendly enough anyway).
As for the aforementioned My Little Pony: The Movie from 1986. IMHO, they likely won't air that until they can air both the two original specials (preferrably the original broadcast versions), and the My Little Pony 'n Friends TV series, and if it's true that "Applejack" and "Spike" really are the only names from the show that Hasbro still owns the rights to, then that could be a problem (that, and the fact that the TV show also has three other Hasbro creations...unless that doesn't actually have anything to do with it).
Cartoons aren't "just for kids"...but they're not just for adults either. They're for everyone.