Actually, it's not so much the "fan club" bit (though that's there).

Some of it is giving folks (the ones "in charge") the chance to be a big fish in a little pond.

Some of it is having a "tribe" to belong to. That's similar to "fan club" but tends to cover more areas of life and lead to greater amounts of drama.

And then there's the power the leaders get and the "don't have to think" (and the related "I'm special" and "we're right"/"we're better than these other folks").