You got it right BB,
The WT avoids ever mentioning the real reason many are partaking: They (the partakers - at least some of them) are coming to the realization that it has nothing to do with a heavenly calling or being anointed. It has everything to do with Jesus commanding it to be done in remembrance of him, what he did. For the WT, this thinking is a poison to them because they have linked partaking to ruling. So that the more who partake (for the right reason), the more diluted their authoritarian position becomes. You can see their angst in the WT lesson yesterday.
The WT scrupulously avoids mentioning that particular option. They don't want it even discussed. They "frame" the argument by establishing the two sides to the argument: (1) The WT way, or (2) the mental problems or past erroneous religious beliefs. Those are the two sides to this problem that WT wants the R&F to see. As far as the WT is concerned, you are either on one side of the argument or the other. There is no third option. At least not as far as the WT is concerned. And the WT wants it to stay that way.
And they don't want the R&F asking those who partake for their reasons. Such questions risk letting the cat out of the bag and getting the R&F to start thinking. To start discussing this option without WT controlling the discussion will only lead to more people coming to the correct conclusion.
Surely they know that some are taking up this point of view. And you would think that if they saw this as just another erroneous position, that they would compose an article to refute it. But they don't. They scrupulously avoid even mentioning it (as the OP wondered, and as that 'framing' tract I linked to instructed). The WT not mentioning this particular idea is an evidence (from silence) that they are purposely using this strategy to keep that particular idea away from the R&F.
It's not all that different from the religious leaders in the 1st century not wanting anyone to converse with Jesus or his disciples. They were trying to contain the damage to their position. (Jn 11:47-50)
By NT standards, the GB have already condemned themselves as opponents of Jesus. (Rev 21:8; 22:15)