When a person joins the jw organization, do they make a statement claiming that they totally renounce any other religion ?
Interesting thoughts. Some things make more sense (at least to me), when I make a difference between religion, religious organizations, religious based businesses and cults (also known as high-demand, controlling groups). What and how people live, the things they need/have to do after they walk away from any of those, they all vary depending on what they are leaving. That is, not to mention that some people are kicked out, like Dfed people.
Please bear in mind that controlling, manipulative organizations always give the illusion that the controlled people are making a decision on their own, hence they always stay away from negative statements such as "renouncing other religions".