We all gossip. It is only human. Watchtower actually tries to instruct adherents not to gossip and it can land a JW in front of a judicial committee—some do try to follow this admonition. But then, that doesn’t seem to contain the storm.
And there are likely other groups that might outdo JWs, but do you believe that JWs gossip more than average?
I suspect that the heavily judgmental nature of the organization, the many rules that make mountains out of anthills, and so forth, the announcements of judicial decrees, the midweek pioneer cargroups, set the conditions that make gossip not only inevitable, but rampant.
Take the bunker videos at the recent convention, where folks sat around and gossiped about “Kevin”. It is almost an instructional video teaching people to gossip about those who are not towing the line.