From an interesting speculative article I read on this:
“The world the Turpins created for their family had so little contact with others – Louise didn’t work, David was apparently not sociable and the children were home-schooled – that they may have considered their actions normal. Protecting their children from prying eyes became a way of life. They may have thought that what they were doing was right. But as time went on, they might have become more desperate and only able to control their offspring with threats and chains.”
Obviously we don’t know for certain, but it brings to mind an image of cultish families who believe in having as many kids as possible and keeping those kids as isolated, sheltered, and subdued as possible, and this becomes increasingly difficult to achieve, especially if the family can’t provide for all the kids financially; as a result, the parents’ actions become more erratic and desperate. The article also referenced the way some of the “before” photos portray the children almost as novelties and decorations: always wearing identical clothing and serving as a backdrop for the parents’ photos, not being treated as individuals. That’s reading a lot into it, but it’s something to consider.
This case is interesting because it occurred in a claustrophobic housing tract (when I first heard the story, I was picturing an isolated ramshackle compound out in the woods), because there are “before” pictures on social media that reveal normalcy, that do not show emaciation. The downward spiral must have been very quick and dramatic.