They absolutely do not want anybody to know that somebody left because something is wrong with the religion.
That's been my experience, too. I allowed myself to be stumbled, or succumbed to materialism, or just got tired of running the race, and the list goes on. Those are the kinds of things they say about me. Ironically, no one has actually asked me why I left - after nearly 30 years, more than 20 as a popular elder considered a "pillar." You'd think somebody would be curious. But no, it's almost like they're afraid to bring it up. It seems to me they already know the answer, which is why they never ask the question.