It's an interesting phenomenon and I think the consequence of a belief system that there are two eternal hopes even though the Bible only speaks of one. With JWs, you get the division of an earthly reward and a heavenly reward. As a Christian (never a JW), I can say that I don't feel I'm better than anyone else or have an anointed feeling that I'm somehow elite or more special than others. In fact, it's quite the opposite; the Christian life includes times of discouragement, uncertainty and disbelief that God somehow wants me (but He does!). So, if presented with the idea that there is an earthly and heavenly hope as JWs are, I wouldn't think that too many people are going to say, "I'm somehow different therefore I have a heavenly hope that is reserved for 144,000 people in the world for all time."
Add to that, the social pressure of Jehovah's Witnesses and a heavenly hope pretty much being looked down on (such a strange reaction by the way), you're going to have the situation where only people who read the Bible for themselves (Hernando); the mentally unstable; and those with delusions of grandeur that they are somehow different than other people are going to come forward and say that they are heavenly bound. Yes, all Christians believe in some sense that they are chosen by God but not in the sense that only 144,000 of them will be with Jesus in heaven because there are plenty of verses that open it to whoever believes in Him: as many as believe in Him are children of God (John 1:12). So it's not a matter of being special or different from others. It's a matter of being the called out ones, the ecclesia (church).
As an aside, I am still not sure how this doctrine is even propped up the way it is. Revelation 5:9-10, which is used to support that the 144,000 are the only ones ruling with Jesus, actually refutes that assertion for one of two reasons. First, those words are not attributed to the 144,000--Revelation 5:8 refers to four living creatures and the twenty-four elders. Second, verse 9 says [the Lamb/Jesus] has redeemed us to God by Your blood out of every tribe and tongue and people and nation." But the 144,000 are from the tribes of Israel (Revelation 7:4-8). It is the great multitude (crowd) which no one could number that is of all nations, tribes, peoples and tongues (7:9). So it is the great crowd that have been made kings and priests (or a kingdom of priests) to our God.
Revelation 5:8-10 (NKJV)
8 Now when He had taken the scroll, the four living creatures and the twenty-four elders fell down before the Lamb, each having a harp, and golden bowls full of incense, which are the prayers of the saints. 9 And they sang a new song, saying:
“You are worthy to take the scroll,
And to open its seals;
For You were slain,
And have redeemed us to God by Your blood
Out of every tribe and tongue and people and nation,
10 And have made us/them kings and priests to our God;
And we/they shall reign on the earth.
After these things I looked, and behold, a great multitude which no one could number, of all nations, tribes, peoples, and tongues, standing before the throne and before the Lamb, clothed with white robes, with palm branches in their hands