Without DFing everyone who was a witness would be a witness because they wanted to be. They would live as they thought best and could use Watchtower information (and other information) to form their spirituality.
DFing is the underpinning to a universal false unity. Unity through coercion is not unity.
Jehovah's witnesses are no more unified than any other organization, but DFing allows them to say, oh yes, we are all the same, otherwise you would no longer be viewed as a witness.
So, people hide their thoughts on doctrine and their feeling on moral issues.
Joel