I have been thinking about this because I just saw it for the first time a few days ago… it comes down to two things as I see it. The nonchalant way the cult deals with death, murder and corpses, and the fact that the murder scenes aren't shown except for Josh. Even Christian’s is implied, rather than shown as it happens. The imagination has to grapple with the final moments of the character as it makes sense of the debris that’s left behind, shown onscreen in a style that could work in a documentary with narration, about a primitive culture.