You sit there and wonder, "why aren't these idiots doing anything to try and escape?"
But then you realize that's the point. It's a character study metaphor, where the director wants you to wonder that, because the guy at the centre of it all who is too dumb to even try to escape the cult is also letting himself be stuck in a relationship he's not happy in. "Why doesn't he try to escape the cult?" runs parallel in the movie to the question, "why doesn't he leave this relationship he's not happy in?"
It's an interesting parallel to make. However, it doesn't make for a very engaging central character, since he's just confused and passive for the whole movie.