It seems like Disney sometimes just decides not to pay people, and by and large gets away with it. It's just like the Alan Dean Foster issue.
Many legal issues are murky. There's a lot of gray areas, and small details that can make a lot of difference. And I will admit that I haven't read that actual contract involved. But I find it really, really hard to believe that this exact situation (theatrical vs. non-theatrical release) isn't spelled out pretty clearly in the contract. Hollywood contracts are notoriously long and arduous exactly because they spell out all this stuff down to a very, very fine point.
I'm disappointed in both the legal system and the various Guilds for not going after Disney harder on these things.