What makes belief so powerful, among other things, is that the way humans deal with reducing cognitive dissonance is almost always toward the direction of maintaining the status quo, especially when the dissonance relates to oneself personally.
1) Your favorite actor/musician/athlete is busted for pedophelia and the evidence is overwhelming.
Cognitive dissonance ensues because there is a conflict: you really like and respect the guy versus he's accused of pedophelia. How do you reduce the dissonance?
"Well, he's just an actor/musician/athlete, not a role model. I can still like his movies/songs/team without liking him personally."
Easy to do because the dissonance isn't all that personal and the consequences are not all that serious.
2) You are shown evidence that thousands of leaders of your OWN religion have been accused of pedophelia. Many of them did jail time. Some were DFd and many were not. The religion has paid out millions of dollars in settlements to victims of pedophelia. The religion has DFd many of the victims of pedophelia for speaking out publicly about their experiences.
Cognitive dissonance ensues because there is a conflict: this is YOUR OWN religion that you have dedicated your life to believing it is God's CLEAN organization versus this is a religion that does not deal with pedophiles or their victims in a just or loving way. How do you reduce the dissonance?
Because this touches on YOU much more personally than case 1, you are more likely to reduce dissonance by discounting the evidence as anecdotal, exaggerated, and isolated incidents. "This never happened to anyone I know. My congregation elders would never do such a thing. Slanderous gossip about such things is unchristian. That rumor was probably started by some disgruntled apostate. The entire pedophile issue is a bunch of lies endorsed by Satan."
Changing your own viewpoint or the status with which you view someone or something personal and dear to you is incredibly difficult even without the influence of cult mind control. But being in a cult like the JWs makes it even harder.