I think people have forgot what an actual cult is.
Not all cults have a charismatic leader, although the Watchtower was originally led by Charles take Russel, who was considered a charismatic leader in his time.
I think you need to educate yourself on what a cult is. Absolute isolation and control describes some cults, but not all, what makes a cult is the things they do to control their members as described in my post above, and you can't deny the Watchtower uses control, deception, intimidation, relationship control and a clear reporting structure.
No member of a cult believes they are in a cult, that is part of the deception. But if a group teaches that they are the only path to salvation, tells you who you can talk to, encourages members to report bad behavior and hides their history and practices, then they are a cult, no matter if they have a single leader, or a body of leaders, or what clothes they wear. Those are surface trivialities.
If it walks like a duck.......