>>10477537>>10477648>literally nobody wanted the toa form of a character they probably misinterpreted as a bad guy. It sounds ridiculous because it isn't true, at least if you believe what Greg says. According to him, the sets were designed without any particular characters in mind, and having them be Nidhiki and Dume was simply a suggestion that was rejected by Bob Thompson (who apparently wanted to save the characters for a later story). Picrel is from one of Greg's BZP Q&As.
I can't find anything saying Lego was even involved in the choice. Come to think of it, I don't think there's really any evidence of TLG exerting control over the Bionicle team outside of deciding how long the line would go for.