Oh, I know, I meant the audience, the 2004 Bionicle fanbase. There was no other knowledge to the contrary at the time, and the returning audience from Mask of Light was already aware that Makuta is the bad guy. Sorry for the confusion.
Maybe so, but I've never known that phrase to be used without certainty. Telling Onewa that Onewa doesn't want to know who's in charge implies a knowledge of who is in control on Vakama's part. Vakama isn't divulging the info in-universe because there's no time to explain (regardless of who, someone is endangering the Matoran as they speak, and he's cut off seconds later by Vahki), but in reality it's to create suspense for the name drop.
I wouldn't put lazy writing beneath a direct to DVD children's movie.
Looking at you, Web of Shadows.
As he always should!
I'd agree on that, but I still believe the movie makes it obvious Dume is Makuta.
His staff top is the toy form of the Mask of Shadows, the entrance to the Cave of Unending Whispers is the movie version, they show Dume talking to Makuta in one scene, and the scene right before the one in question blatantly reveals they're the same anyways.
Even if the more subtle clues were missed, there's no reason a viewer should be shocked to find out Makuta is Dume when the big reveal in front of the Toa happens. Pumped perhaps, but not surprised.