In my opinion the demand for a government controlled kill switch in every piece of hardware that is somehow able to harm people is much more threatening in so many ways than the insecurity the author is trying to reduce. Just a few:
1. Based on the asumption, that ones current government/state is for the good of all people, what gives him the confidence that this will stay that way? What if your beloved government goes rogue? That's a lot power for an autocratic regime.
2. Why even trust the government in the first place with that kill switch? They are the same people which are careless about infrastructure critical ITSec since decades.
3. An univervsal security module which is highly standardized is a very profitable target. While the author is aware that finding an attack vector of one particular vehicle can mean that all vehicles of that type can be compromised, he doesn't come to the conclusion that the same logic applies to his security module.