There again, I think the comparison fails.

Fixing the hospital: single place to work on, easier

Blocking all the roads/flights: everywhere, harder

Vs

Fixing all the telnet: everywhere, harder/impossible

Blocking port 23 on an infra provider: single place, easier

It makes sense to me to favor the realistic solution that actually works vs the unrealistic one which is guaranteed not fix the issue, especially when it's much easier to implement

I run telnetd on 2323 because I don't want hackers to find it.

The hospital-plural-s: many places.

Roads: a lot more places than that.

The core of the analogy holds.