It's very easy to play with lives that aren't yours.
It's a familiar example of the perennial "[THING] could be solved overnight if [PERSON_OR_GROUP] would just start taking [THING] seriously" trope.
The best response to a cyberattack on critical systems is to take security seriously. Document the offense, avoid the same mistakes and invest in penetration testing. Of course, nobody is incentivized to do that until they're attacked, so the cycle perpetuates itself.
When appropriate. I.e. never.