It is an essential part of having control over the membership. I would not have dreamed of even making eye contact with anyone who was identified as an apostate, much less listening to anything they might have to say. Until I left, the only things I knew about Ray Franz was that he was Fred Franz's nephew, had served in the governing body, and was an apostate. I wouldn't even search for info on him until I knew I wasn't a JW anymore.
It's an effective approach, to terrify people into avoiding those who could damage their faith the most. It shouldn't make sense- if you have the truth, falsehoods aren't something to fear. But irrational fears seem to be the most powerful.