2 years ago I asked everyone on this forum to post what their religious leanings were after leaving the JW organization. About 90% of those who responded stated they were atheist.
I think this atheistic end-state for ex-JWs is because the Jehovah's Witnesses religion is a 100 year young religion (kind of a recent hodgepodge of paganism, Judaism, Christianity, and humanism) and is not Christianity in any genuine sense. Like Mormanism it borrows "some" sacred writings from Christianity and "some" words and "some" concepts about God, but then it makes up new "light" or new revelations that greatly modify the meanings of the Christian writings (and even modifies the writings themsevles) to the point where the final religion is certainly not Christian in any meaningful, traditional, or historical form.
Therefore, it is not proper to say that ex-JWs have "left" Christianity, for they were never a part of the real thing.
Christianity is a living relationship with Jesus Christ, and regardless of which "church" you choose to attend you can pray to Him, He forgives your sins immediately, He sends the Holy Spirit inside you to regenerate you (make you born again), and He gurantees your redemption with no fear of a surprise rejection at the end of your life or at the end of time. Since none of that is true for ex-Jehovah's Witnesses, they should never think that they have ever been "Christian."
It was not Christianity they rejected, but a counterfeit johnny-come-lately hybrid religion where the human leadership seated itself in the role of judge and lord--roles that only belong to Christ. You have not left Chritianity, you have left the Watchtower.