Earlier quoted context omitted.
Satoshi was in favor of digitally signing Bitcoin transactions to provide non-repudiation as an underpinning of Bitcoin ownership. > it is more important what is in the message than who wrote it. That statement actually favors the signing of this textual message, since digital signatures provide integrity control in addition to non-repudiation of origin.
Satoshi could be a whole building of people, we don't know who he was, and so it's not even clear what "authentic" would mean in his case. Integrity of the message doesn't matter - if you see a message and it makes sense to you, then that is all that is necessary. You can agree or post a response to argue a point. If it's something stupid, what does it matter that it's signed? And if it is from "Satoshi Nakomoto", ho…
In this case you can get all sorts of sybil attacks to manipulate consensus by sheer numbers, including fake news and so forth.
Imagine HN without reputations or limits on spoof accounts.