If you were an adult and fell for this, I just don't understand it.
Actually, it was quite easy to fall for it once upon a time. Before the Internet came around to everyone, people could take the litter-ature and read it. There was nothing to compare it with, and finding dissident material involved a search in the library or a Christian bookstore. Of course, the litter-ature bashed such sources as from Satan, so people would not bother making the physical trip to those places to find out more.
Besides this, the Suffer Forever book and its successors (and predecessors) made false promises. People were misled to believe that, if they did what those books said, that they would gain everlasting life on a paradise Earth. They intentionally left out the past failures for these promises to come true. You get in based on this, and soon you find yourself required to go to all the meetings and then spread the cancer to everyone else. Ultimately, you have to join the organization. Once there, you are not just discouraged from reading other sources--you are banned from reading them. Then nothing happens.
These days, there are still a few people without access to Internet. Those will still face the same hardships in comparing the scam. For most with Internet access, it is only a mouse click to all those sources that you need to compare with the books, not a physical trip to some demonized church store. But even so, there are still people that are getting scammed because they tend to jump before thoroughly researching the subject.
The motto is "Shame on you if you fool me once. Shame on me if you fool me twice." This applies to anyone that, after seeing the Watchtower as a scam, returns (aside those who return solely and exclusively for the sake of keeping families intact, which the Watchtower Society uses to keep people in that otherwise would have left or stayed out). That is why I cannot see why a person, having once been one of Jehovah's Witlesses and having left, and in the absence of family influence, would ever even think seriously about going back.
As for those who were scammed once, they definitely should pay. And they should pay even worse for those who were born into it, without a choice. Those people suffer the worst. They lose out on childhoods along with all the Christmas specials and after school events. And sometimes even the parents were born into it. Definitely, the Tower has to go.