You're arguing that because a gun or car is dangerous, ownership implies liability. There are few things which can be possessed which cannot be dangerous in the wrong hands, and a car is not actually intended for the purpose of murder, so one should probably not judge it by that standard. However, I did explicitly consider the case of an inherently dangerous object, so I cannot have left out that part as you suggest. I am really not sure what part of this concept you could possibly have an objection to. You know we're talking about a car, right, not a hydrogen bomb? Surely you can do better than that?