> leads me to believe that such cars had negligently insecure encryption
While accurate, the standard may not be as rigorous as you'd like to imagine; there was a time not long ago when a wire coat hanger was enough to unlock a car.
I remember that time. We even used it once on a friend's car. However, we did not ban wire coat hangers. I'm sure the politicians would agree that would have been silly, but common sense seems to leave them when it comes to tech.
While accurate, the standard may not be as rigorous as you'd like to imagine; there was a time not long ago when a wire coat hanger was enough to unlock a car.