The argument is that the Globes only view a musical as non-diegetic (it only takes place in their heads or an alternate reality instead of being heard by everyone). It becomes a music drama, instead of a musical, in their eyes once the music is being used in concerts, performed for others, etc. Except this argument falls apart when you look at beloved film musicals like Cabaret lol.Thought Vice was a drama? Wonder why they didn't go musical category for Star, Bohemian??
EDIT: quoted the wrong person. Sorry lol.