© Charles Chandler
Cult leaders begin as part of a larger society, and their targets are members of that society. But the cult leader becomes frustrated with the fact that he can talk people into doing things for him, but as soon as these people return to their daily lives, the effect wears off. Getting people to do things against their natures is hard when they are surrounded by family and friends who nudge them back towards more reasonable behavior. Eventually, the cult leader gets tired of spending hours working his targets into devotional frenzies, only to have to go through the same exercise a week later. If the moderating influence of family and friends can be removed, the leader can talk the targets into doing things against their natures, and they won't go back to normal anywhere near as fast. If the followers can be isolated from moderating influences, the leader can get more ego trip with less effort.
Isolation from society can be accomplished in degrees. At first, a small group of people might decide to rent a large house. Next, they might decide to purchase a tract of land and to build the facilities to accommodate a larger group of people. Isolation can be partial, wherein cult members live with each other, but still work in the community, or it can be total, wherein the members are completely cut off from society, and especially from the bonds of family and friends.