Getting back to the letter, if someone believes counter doctrines that are diametrically opposed to what the Bible teaches, why would they be associating with Jehovah's Witnesses?
If a person believes all the doctrines taught by orthodox Judaism for example, why would they be in a Kingdom Hall if they reject Jesus as the Messiah?
It's not about being in the Kingdom Hall if they reject Jesus. Many feel trapped in the Kingdom Hall because they have come to know Jesus as the Messiah.
But the WTS claims to be the only Channel to God rather than teach what the Bible evidently says: That Jesus is the one Mediator between God and men (all men).
Unfortunately you don't seem to have eyes to see that or ears to hear it. You're blinded by the traditions of men and maybe one day you'll understand that
some who go to the Kingdom Hall, have to, because otherwise they would be shunned if they revealed they love Jesus more than some man-made organization.
We are the "conscious class," and there are thousands of us. Deal with it. (Matthew 5:3)