I've heard it several times from other friends that I have that have left. Almost all of them at one point or another have said, "I always felt that if the Watchtower didn't have the truth, no one did". It makes sense. The WT instills a hatred for all other beliefs. That doesn't go away just because you leave the Watchtower.
I always look for a chance to resurrect this particular horse. Do you suppose that much of this attitude is driven by the fact that JWs really aren't religious or spiritual? By that I simply mean the thing the believe in is that they have figured out the key to the end of the world and that they are better than everyone else.
Most anti-conversion stories with the JWs center on some discovery that, golly, the JWs really aren't morally superior to everyone else. I think that lends some support to my claim.
As for the spirituality thing -- my personal experience growing up JW was that really religious people were mocked by us. Born-again, evangelical, or other charismatic Christian types were really thought to be strange by us JWs. I think that attitude isn't supported by people who are religious themselves.