I was disappointed that this particular episode made no mention whatsoever of Longo's JW past. That's too bad, because it's a big part of the story. The closest it came to doing so was that it said he and his wife had been members of the same congregation, though it still didn't say it was a Jehovah's Witness congregation. The Fatal Devotion episode of the Final Witness docudrama series revealed a lot about Longo's JW background and implied that the increasing stress of trying to present the image of a perfect Witness family played as much a role in this horrific tragedy as did his innate narcissism and hypocrisy.
I completely agree that his simply being a JW, or even the humiliation and disgrace of being disfellowshipped, did not directly cause this unspeakable act of betrayal. But I would argue that the constant pressure of feeling forced to keep up appearances, coupled with the increasing responsibilities of providing for his family, certainly laid the groundwork. It's easy to see how he could have fallen into a "drowning man" syndrome.
Now that doesn't excuse his actions in any way whatsoever. Plenty of other people feel overwhelmed and don't know which way to turn, but they don't murder their family and run off to Mexico to start a new life like nothing ever happened. That's what a psychopath does. I do think Longo is psychopathic, narcissistic, avaricious, conniving, and self-serving to the extreme, but I don't think he's clinically insane. I think he's evil. He deserved the death penalty, or at least four consecutive life sentences without parole.