I would pretty much guarantee most who say its a cult have been disfellowshipped and have regrets.
E.G. someone may have passed over a career opportunity because they wanted,, at the time,, to prioritize preaching. And years later leave the cong. then regret and become bitter.
You should really spend a lot more time around here and you'll find that you couldn't be more off base. There are many who are still 'in' and believe it is a cult. I was never DF'd, and I really have no major regrets and made only a few sacrifices for the cult, but still strongly feel that it's a cult. In fact in some ways the cult kept me out of trouble and benefited me. In the end my greatest regrets are how I treated a few people that weren't in the cult and that I allowed myself to be controlled and sacrificed my intellectual honesty for so long.
You also state that the dictionary definition of a cult is that it must have a charismatic leader - well the founder of JWism, CTR, was that person. His successor, who I'd say really finished the job of turning it into a cult, was also a single charismatic leader. Generally cults are relatively small, but this one grew large and was thus eventually able to sustain a group of leaders, but the concept is the same. Your use of this point to rebut the description of the JWs as a cult falls flat.