JWs embraced the new teaching from the GB about the overlapping 1914 generations, because they could postpone their day of admiting, that the WT religion is a complete farce and they have wasted their entire life.
Now the reality sets in- they will likely die soon, without seeing the fruition of all the grandiose WT promises of the New System of things. Next comes depression as their mind tries to block out the truth about their sorry-ass religion- the world at large understands the WT religion is a false prophet and is dangerous to people and this instinctive fear of their false message, manifests itself as a disdain for the WT publisher/pioneer stooges who go door to door seeking converts.
Finally, knowing that they are not going to convert anyone must be a real drag on their public preaching- in fact, the more they go out preaching, the more they are likely to meet someone (like you or me) who will successfully crack their blind loyalty to the WT org.
I don't even have to debate doctrine with a JW to win- all I have to do is ask the JW one simple question-
"Are you happy?"
and the followup to their "yes" answer
"you need to stop lying to yourself- you don't fool me and you don't fool God"