As usual, the JWs answering this question beat around the bush instead of simply answering the question. So the rest of us, will pick up the slack and simply answer it. The answer is: Because this is typical of separatist groups, including religious ones.
High level control groups do this often - and not only religious ones. If you look at extreme cults like jonestown, they were willing to kill you if you tried to leave. Even today's religious groups like Mormons and Scientologists make it hard to leave.
Certainly they also make sure that if you leave, they will drag your name through the mud. Islam is also hard to leave, and in some muslim cultures you can be killed for trying to do that. Even high level control political groups will do this as well.
Think you can leave CUBA if you want? Try again.... In the Watchtower Organization it's similar. Sure you can just write a letter and dissassociate yourself, but the organization has created a stigma around that, to make sure that if you leave, people will look at you as a sinner, rebel, wicked and the typical nonsense concept of "leaving Jehovah", as if the Watchtower society was God.
The Watchtower believes that their church is the Ark of Noah's day, today. If you are not in the Ark, and you have had ample time to come inside, you will be destroyed just like the people were in the flood story of the Torah. Therefore, from their perspective, leaving the Watchtower Society is like signing your own death warrant.
There would be no reason to do such a thing when you could just save yourself by remaining/becoming one of them. This doctrine has perpetuated untold suffering for millions of people including myself.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.