I think the reason why ex-jws tend to become atheists is probably because the WT does such a great job at emptying a person of their spirituality. As humans we all have a spiritual dimension, but spirituality has nothing to do with pioneering, giving comments at the meetings, making many return calls, or humbly accepting any doctrine or policy they promote without questioning it. But this is what spirituality is for them. The WT god is the organization.
They also destroy a person emotionally on different levels, don’t have independent thinking, pride (as in questioning the elders), don’t trust your own heart, follow orders even if you don’t agree (be submissive), etc. So once somebody gets fed up of all this crap and leaves, he will naturally be apprehensive about religion and God.
If you didn’t manage to keep a sense of spirituality apart from all the rubbish they taught you, once you free yourself from them, you will also stop believing in God, as all along you were dealing with a false god, their organization. Nothing to do with true spirituality. It is an evil and destructive cult.
You will know the truth and the truth will set you free. (not enslave you) John 8:32