I think we come to forks in the road throughout our lives and whichever direction we happen to choose, we deal with what we encounter and those encounters become our life story.
I think those who become JW's on their own (not born in) are already a bit lost or are searching or are heading for a fall and having any kind of strong direction in their lives is an improvement. JW's are out there actively recruiting people and the odds of them finding and attracting lost ones is very high. How many people do you know who were doing really well in life already, joined the JW's as adults? In my experience, it was more often than not, those who were at a vulnerable stage in their lives who became JW's.
Healthy organizations like to see personal progress and growth among their members even if it takes them beyond the group. JW's want to squelch the individual,cripple their critical thinking abilities and teach them to fear that which is outside the group. I think many who encounter JW's and stay with it for a good period of time and then leave, on some level are still convinced that they are bad people or possibly cursed in some way for having done so. That belief becomes a self fulfilling prophesy for them and they head straight for what they believe they deserve.