No you've got it but maybe don't see the value of it fully.
It's pointing out an instance of transgression, not articulating a general rule. There probably is or needs to be a rule as well, but this doesn't by itself tell you what it is or define its bounds.
You want to separate the definition of a rule and its enforcement. Even if the rule is just an informal social one among a friend group this is valuable. Think about the common trope of someone in a group making a joke about a car accident, potentially funny, but not knowing someone else in the group recently lost a parent in a car accident. You shut them up tactfully and then give them the context of the transgression later and potentially debate its boundaries then if that's valuable.
What you absolutely don't want is, on the spot, having a public group-wide conversation about jokes about car accidents. Are they ever ok? Ok when someone isn't grieving from one? How long a buffer do we give for grief? Those are probably useful questions for this group to tackle, but this is the wrong time for it. "We don't joke about that" is good enough for now.