Even while writing pseudonymously and innocuously you are at risk of being doxxed and subjected to mob "justice;" as an example of this see Scott Alexander's writings on Slate Star Codex.
In light of this the safest recourse is to simply not post anything online at all, for fear of being doxxed at some point in the future (an inevitability given modern standards for and cultural attitudes towards privacy) and subjected to invective for years' old posts and writings. This is the culmination and terminal state of "anonymous nonexistence" you refer to.
In this way the chilling effect achieves totality, and nobody feels comfortable sharing genuine thoughts online at all. It's arguable that this is a societally healthy state of affairs.
Scott/SSC is an interesting example. In my dichotomy of “known people” vs “plebs”, even behind a pseudonym Scott is far closer to the “known people” end.
He writes about (sometimes) controversial stuff for a large(ish) and influential audience. He wants to be known and influential. I think he deserves the right to do so pseudonymously, but that’s tangential to my actual point.
Most of us plebs do not want to be famous or influential, and therefore it doesn’t make a ton of sense to leave a trail of possibly regrettable or easily misinterpreted bits of data attached to our real names.
The Scott Alexander thing is interesting to me in terms of how online dramas work because the drama assumes its own momentum and the facts struggle to maintain the pace.
Scott Alexander was not in fact doxxed. He said in his final post before deleting his blog that the NYT planned to reveal his name, deleted his blog and the NYT published their article three weeks after he had already revealed his own name.[1]
The pros and cons of whether they would have revealed his name became this massive hoo-hah and maybe they would have revealed his name given the chance but the fact is he was not in reality doxxed by anyone other than himself.
In light of this the safest recourse is to simply not post anything online at all, for fear of being doxxed at some point in the future (an inevitability given modern standards for and cultural attitudes towards privacy) and subjected to invective for years' old posts and writings. This is the culmination and terminal state of "anonymous nonexistence" you refer to.
In this way the chilling effect achieves totality, and nobody feels comfortable sharing genuine thoughts online at all. It's arguable that this is a societally healthy state of affairs.