This is the story of a cult and its leader, and their descent into madness and violence. There's a lot of potentially very interesting content here. Unfortunately, the filmmakers don't really handle the content well.
To some degree, it feels like a slow-motion pinball - it touches on various elements and then jumps away before it can go into any depth, but it's so slow in its telling that it feels like molasses. The film brings up the media's role in normalizing the cult; but it moves on before that can be really examined in depth. The film briefly seems interested in what attracts people to cults; but it doesn't take time to explore this. The film occasionally focuses on a former cult member who may have been more involved in everything than what he was punished for; but we don't really get a sense of the evidence. The film brings up the failure of police to stop the eventual tragedy; but we don't get much of an examination of what went into that.
It's like there are parts of four or five better documentaries that are shoved together haphazardly, and the information presented is minimal. This is one where you're better off reading the Wikipedia article than watching the movie. There are worse documentaries, but they're few and far between.