Do we need it at all? As you can see from the discussion, its existence leads to confusion and it's more a genre than a description of the composer. I think it's better to retire it and use either [unknown] or [anonymous] in its place. Same for its siblings such as [classical music] or [christmas music]. [Disney] has its purpose because it does say something about the composer, because he or she was commissioned by Disney to write the piece and Disney usually holds all copyrights as well.
On a related note, let's scrap [dialogue] as well. The current description seems to be there only to justify its existence (which I think it lost when MusicBrainz got artist credits). There's no reason to handle it differently from other tracks or recordings for which the artists are known but not mentioned on the back of the release.