If I recall correctly the part of the system this is running on is independant from anything important and only does media controls. It also speaks to the rest of the car over a network interface.
But still not quite for the faint of heart.
There have actually been a ton of examples over the years of researchers hacking into car systems wirelessly, some of which used the media system as the attack vector.
Even if the media subsystem is running on dedicated hardware, the fact that it's networked with the rest of the car means that there's still a risk of it being used to gain access to other components.
As for the indiscriminate killing of civilians, what else would you call the example from the article?
> in Pakistan, in attempts to take out 41 men, American drones actually killed an estimated 1,147 people (while not all of the 41 targeted figures even died).