IMHO, the most simple expalanation is the extreme variety among ex-JWs.
Let's list just a few of the different types of ex-JWs.
1. Still captive, but not active. Believe it's either God's Organization, or better than all other religions.
2. Disfellowshipped, living in fear of Armageddon, but no intention of returning
3. Inactive, know it's not the truth, but wants to maintain contact with people still inside; cannot give any indication that he's an apostate
4. Disfellowshipped, living in fear of Armageddon, wants to return or open to the possibility of returning
5. Disfellowshipped, confused; have not deconstructed the cult experience, unaware of the ex-JW community
6. Out of the organization, member of a non-Evangelical religion
7. Out of the organization, member of an Evangelical religion; seeks to help save others
8. Out of the organization, atheist, agnostic or apatheistic
9. Out of the organization, depressed
These are just a few of the categories. So, it's easy for me to imagine that many of these classes of people who have almost nothing in common.