Basically its to get people to believe in the things they say and proclaim.
Once people are in a believable mental state and acceptance, then the WTS can control people's thoughts, emotions and actions through acts of repetitive indoctrination.
This all comes together by instilling the notion that their interpretation of the bible is the correct and accurate one. Add in the notion of following us you'll be more righteous in the eyes of god , thereby offering a better chance of survival at the soon to come Armageddon.
Everything connects in a cohesive self supporting way and subconsciously effects the thoughts and social behavior of all those being indoctrinated.
Constantly pointing out the many evils of the outside secular world or other religions as "false" but how one can gain true happiness when inside this organization is their way to sustain devoted members.
Stating that one can gain further righteous approval by participating in Jehovah's will and purpose by being an acting publisher or pioneer.
After all this is God's chosen organization so the leaders of the WTS. say ........or is it ?