I don't know if there is one answer. For example, having met Sam Herd I see where he likely is an "honest" believer. It's all he has ever known and frankly, he isn't the sharpest of the group. He is not the "New Light" instigator.
However, it should be quite clear that "somebody at the top" damn well knows it's BS. Consider the many publications that are now out of stock because they were caught lying and misquoting references and inserting ellipses that changed the meaning of the quote. I'm not sure anyone of the GB actually had a hand in such because frankly, I think the GB are kept busy being figureheads. They might have just rubber stamped the draft copy of said publications. Or, actually believe that some young guy in the Writing Dept discovered some wonderful information and quotes.
Do we know who is really running things?