What is never touched on in the film is the cult's recruiting methods. New recruits are led and mentored by existing members, but there is no indication of HOW exactly the new recruits are convinced.
The disc includes Mary Last Seen, a short the director made on the same location with one of the same characters, showing how this happens. Suffice it to say that it doesn't make this any less creepy.
When Martha is showing Sarah around the farmhouse for the first time, she introduces her to one of Patrick's babies. Sarah asks if it's a boy or a girl, and Martha says "Patrick only has boys". Think about that for a second.
Patrick has sex with all of the women in the cult for purposes of procreation and encourages all of the members to be polyamorous, but it's never mentioned whether Martha was impregnated by him or anyone else and, if so, what happened to her baby.
The cult has some very peculiar ideas about death, so much so that they think death is beautiful, and that when you kill someone they don't really die, they just continue existing in another dimension. Now look at the previous two entries again.
What if there was no cult, Martha had been living with her boyfriend, and just went crazy and started hallucinating him as the leader of a cult (maybe they had a fight, maybe she just snapped).
Or both? Abusive/controlling relationships strongly resemble what we think of as cults. The "cult" of an individual can be based around anything that sets that individual apart and puts him or her in charge of what others say, do and think. A business can also be this kind of "cult".
Near the end, Martha wakes up from a flashback/dream about Patrick and attacks someone who turns out to be Ted back at the lake house. She flees from Ted and kicks him down the stairs, leading to a huge fight with Lucy where Martha is immediately on the defensive for her overall strange behavior. It's easy to forget that this whole situation started with Ted touching a sleeping Martha's leg in the middle of the night, with all the lights off, while Lucy was still in bed. What exactly was he doing?
At first it’s not clear why Martha won’t explain things to her sister Lucy. Why not explain that she was in a cult and couldn’t access a phone?
She may not understand that she was in a cult. She’s still processing what happened. In her mind, maybe she just thinks she was on a farm with her alternative “family.”
She might understandably fear that her sister would press for details. Consider everything that happened to her, and that she participated in, she might feel ashamed and afraid to talk about it.
Patrick may have instructed the others not to tell anyone.
strongly resemble what we think of as cults. The "cult" of an individual can be based around anything that sets that individual apart and puts him or her in charge of what others say, do and think. A business can also be this kind of "cult".