There is only one reason for any control - faulty organizational structure. There are two types of relationships, both of which involve that dirty word that Americans love to hate - submission! Submission, very simply put, is one person or group being led by another person or group. The leaders could be put there by a small group, by a vote, or by coercion/power. Within the submission relationship there is voluntary and involuntary submission.
Examples of involuntary submission would be children, slaves and any others who cannot choose to whom to submit.
Examples of voluntary submission would be churches and other religious institutions (in most cases); social groups and clubs; and relationships, both dating, as well as same-sex/opposite sex friendships. Semi-voluntary submission would be in many work situations where it would be very difficult to find another job but impossible to leave.
For Protestants then, choice of churches is much easier than with other religious groups who much of the time have only one choice in the area or even having to travel far to get to their religious service (i.e. Jews, Muslims, Buddhists, etc. in rural or small town areas).
So then why do people with a choice of churches get under controlling pastors and other leaders? For the same reason they get under controlling spouses and friends as we've examined in prior posts here.
How do these pastors get into their positions? Their organizational structure isn't Biblical. For instance, nowhere in the NT does it say for pastors to start churches with no [bishopric] oversight. I have found generally where there is a lot of control, it's usually independent churches; or churches within a very loose network of churches, such as Word of Faith churches which have little if any oversight. The safest churches usually are denominational ones with good oversight and supervision although at times some could fall through the cracks.
Years ago, many of the Word of Faith churches in my area lost droves of people due to the excessive control (among other things). Many of the members of those churches left and ended up at a large Foursquare church in the area. Although that church was Pentecostal, they had some differences with the WOF teaching. But the former WOF members wanted to go there. Why? The Foursquare church had a balanced, mature pastor as well as oversight from their denomination. I asked several ex-WOF members why they went there and they replied "they felt safe." They also told me they would rather be in a "safe" church than get the WOF teaching. Sadly, there were those who did stay behind in the WOF churches. I would have to classify them as hyper-codependent because God was leading the rest out but these people COULDN'T
couldn't hear God because their codependency got in the way.