I think that the witnesses use the term to further try and control their members. I also tend to agree with psycologist who think such terms are used to brain wash and keep total control if it's members.
A remarkable thing about cult mind control is that it's so ordinary in the tactics and strategies of social influence employed. They are variants of well-known social psychological principles of compliance, conformity, persuasion, dissonance, reactance, framing, emotional manipulation, and others that are used on all of us daily to entice us: to buy, to try, to donate, to vote, to join, to change, to believe, to love, to hate the enemy.
Cult mind control is not different in kind from these everyday varieties, but in its greater intensity, persistence, duration, and scope. One difference is in its greater efforts to block quitting the group, by imposing high exit costs, replete with induced phobias of harm, failure, and personal isolation. Source: Phillip G. Zimbardo, Ph.D., What Is The Message Behind Today's Cults?