I would argue (and bear in mind this is all speculation and dangerously theoretical) that Heinlein’s principle could only ever operate in a justice-based society. In a revenge-based society, arming people does not lead to distributed accountability but rather distributed warfare.
Great observation Talin and completely reasonable and agreeable. That said many people continue to operate or see the world under a just-world lens, where our system of justice is imagined as a Hollywood script. These scenes where ordinary citizens are propped with guns as deterrence or to encourage “politeness” are nothing but a distorted reality and the “sweet revenge” or “avenge me” tropes are a distorted fantasy.
An armed society suggests only one thing, that our acrimony, distrust, and fear for one another is beginning to overshadow the peace, respect and civility that drives human persistence. Why we fail to appreciate this with wayward gun advocacy has always been mind-numbing to me, as it becomes a tendency to embrace devolution at times — which just goes to show how precarious our existence can be with our very own undoing.