My non jw brother, after observing jws at a convention and in one or two meetings, gave us his "analysis" of the gossiping problem in jws about 20 years ago.
He determined that the underlying reason why there's so much gossip was that we formed a society which was too closed on itself and our lives as co-believers are too intertwined.
And so "person A's cousin is the bible student of someone 's sister in law who in turn is the best friend of someone's mother. The mother is in the same congregation as the wife of someone who studied with the nephew of the cousin of the friend of someone who has issues with the daughter of person A (and so on and so forth)". In the end, someone somewhere in the jw world will always know you/know things about you.
I felt it makes sense. I've been paying attention since then and it's so true. Our lives are too intertwined. Of course other reasons are part of the equation.