Was it a hacker? Nope, just a dumb mechanic that got trash deep into the air intake during a routine oil change.
How many (dumb mechanics)*(routine oil changes) are there in this country? Five-Six orders of magnitude more than auto hackers, which is why I don't see any harm in one more (where the driver knew ahead of time it was going to happen).
Here's the good test: since humans were involved, how did they present this to their ethical review board?
I'm pretty confident the answer would be "what's an ethical review board?".
These people, on the other hand, knowingly and deliberately disabled a car on a highway. Yes, they had a plan, but they are still running their little experiment on other unwitting drivers on the highway. I don't consider the manner in which they ran their test to be ethical; it should have been performed on a closed track.
You can't just waive it away because other risk is more dangerous across the entire nation. Under that standard: One little murder is a rounding error compared to the 2.5 mil who die each year.