Same applies to much of IT - without electricity(food), it stops, without cooling(special care), it slows or stops, without careful nurturing in a special environment (alpha testing in a closed system), it won't mature (grow).
And yet, short of death or severe damage to certain parts, we're self-healing without completely halting basic operations - you can break an arm and still walk, and we have redundancy - you can lose a kidney and still pee, you can lose an eye and still see.
It's scary because it's our *lives* that are under threat, not our access to facebook.
"Your computer crashed? Reboot it. If it keeps happening, call a specialist or replace it."
"Your pacemaker crashed? You're dead."
Also, terrorists. What's to stop IS from doing it once or twice (or as many times as they can), killing someone by faulting their pacemaker, and claiming publicly "We killed him!"
We shouldn't underestimate the public panic that could cause. Look at what's happened to many of your "freedoms" since 9/11.