Maybe you're right. I was thinking "I see delusional Christians all the time so why spend two hours or more watching delusional Christians?" But maybe the movie is about it and the approach to Christian's delusions and it gives me some insight on how to deal with them, considering that the main character is a psychiatrist.
teachings of the Bible are so muddled and self-contradictory that it was possible for Christians to happily burn heretics alive for five long centuries. It was even possible for the most venerated patriarchs of the Church, like St. Augustine and St. Thomas Aquinas, to conclude that heretics should be tortured (Augustine) or killed outright (Aquinas). Martin Luther and John Calvin advocated the wholesale murder of heretics, apostates, Jews, and witches. - Sam Harris, "Letter To A Christian Nation"