Scott Alexander's last name is also easy to find. His first name is Scott, his middle name is Alexander, he's a psychiatrist, and he lives in Michigan. This is all information he publicized.
And he has also published under his last name, even on SSC, within the last decade.
My implied wishes (and really, his wishes) aren't terribly important. If either of us do something newsworthy, it's not doxing to attach our name to the news.
Also, if merely linking a real name to a pseudonymous online identity is doxing, then Alexander self-doxxed himself by republishing one of his SSC posts under his real name (while noting their origin) in book published by Springer.
An accurate definition of doxing would contain several components, a few of which would be: it's not doxing if you make the link yourself, and it's not doxing for a 3rd party to repeat the link you made (akin to the first sale doctrine).
Publishing under your real first names, and letting people know where you work, is pretty far from "perfect isolation", isn't it?
He's not stupid. Why did he chose such a terrible pseudonym?
Retconning SSC as an "anonymous" publication is silly, though, and really dilutes the efforts of people who truly want to or need to remain anonymous.