It's also weird that the author can set up this thought experiment such that consequentialists are not able to consider the punishing of innocents as part of the outcome. The entire argument seems to hinge on them only being able to assess morality by the outcome, but a specific step in a process can also be present in the outcome.
Process: you punish innocents
Outcome: societal effects + you have punished innocents.
You would be hurting innocents to punish another.
There is a word for that - terrorism.