Whenever I write about the death penalty, at least a few of those who disagree with me fall into this sort of language (I'm not quoting any of them verbatim, but I think I'm accurately characterizing their argument):
"Society has a right to defend itself from e.g. murderers and to retaliate against them. The judge, jury, executioner et al. are acting as society's defensive/retaliatory proxies when they convict and execute a murderer."
Bob (a member of "society") is duly convicted of, and sentenced to death for, the murder of another member of "society." He is later executed. Still later, new evidence arises establishing his innocence. Since the judge, jury and executioner, acting on behalf of "society," killed an innocent man, should a random member of "society" be executed as a defensive/retaliatory measure?
I've only asked that question, in anything resembling that manner, once so far. The person I asked it of did not answer.
My own thoughts:
Some libertarians deny the existence of "society." I disagree on that specific denial, but not on what it implies.
"Society" isn't a particular thing. It's just a word used to describe an aggregate of human beings who share (or, if no longer among us shared), universally or nearly universally, some particular characteristic or characteristics such as speaking the same language, living on the same land mass, or being ruled by the same state.
"Society" isn't a person, or even a real thing. It's just a loose descriptor.
It's not something that can have "rights" apart from the individual rights of the individual people who fit the description. Nor is it something that can, itself, act.
Those who claim to be acting as proxies for "society" in ordering or carrying out executions are trying to evade culpability for their own actions. That excuse -- "society made me what I am, society made me do it" -- that doesn't seem to fly very well when it comes from the defense at trial. And it doesn't fly very well going in the other direction either.