Nikolas - if the Watchtower is a cult, as so many people in here believe, is Christianity itself a cult?
I believe that Steve Hassan answers your question in "Combatting Cult Mind Control". It depends on how one defines a cult. Cults can be religious, business, etc. Christians have done a lot of bad things for the last 2,000 years, so have people, who are not religious, and so have governments. Organizations are composed of people, so why not ask, "Why do people form mind controlling cults?" or "Why do people join mind controlling cults?"
People can choose to blame Our Father, Jesus Chris, and the Holy Spirit or they can look in the mirror and remind themselves that Jesus Christ did warn mankind about false prophets and now individuals are responsible for taking appropriate actions. I like Benjamin Franklin Gates' dialogue in National Treasure about interpreting a passage in the Declaration of Independence, "If there's something wrong, those who have the ability to take action have the responsibility to take action." It is always easier to blame someone else instead of taking responsibilities for one's own actions or lack of action.
Mt 7:15-23 (NIV 2008) 15 “Watch out for false prophets. They come to you in sheep’s clothing, but inwardly they are ferocious wolves. 16 By their fruit you will recognize them. Do people pick grapes from thornbushes, or figs from thistles? 17 Likewise every good tree bears good fruit, but a bad tree bears bad fruit. 18 A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit. 19 Every tree that does not bear good fruit is cut down and thrown into the fire. 20 Thus, by their fruit you will recognize them.
21 “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven. 22 Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name, and in your name drive out demons and perform many miracles?’ 23 Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!’
Peace be with you and everyone, who you love,
ABibleStudent