I find it obscuring to take what is essentially a math problem and bury it inside a novelette. Perhaps some prefer that. Since conciseness is no concern, including the symbolic form that the logic arises from would clean Ben's argument immensely.
The notion of all or nothing causality, such as when Larry handed Tom the gun, is needlessly simplistic and doesn't reflect reality except in rare cases. More often there is a network of causes and contributing factors. Ben would have a better understanding of causality if he had to calculate risk and efficiency in a factory setting. All or nothing simplification would have little value there as well.
You should also consider the audience. It is likely the audience that would prefer your approach would not need to talk about this at all. They'd understand it with a few simple words.
Distilling it down to mathematics though will not reach a lot of people. I believe those are the likely audience for this particular article.
The target audience matters. He didn't tell me anything I didn't know in this piece. Yet he did frame it in a way that might wake some other people up.