(tangent) That referenced Scott Alexander article was how I figured out his real last name before the New York Times doxxed him - he gave so many details about his brother I realized who he was talking about.
FWIW, I don't think he wanted to hide his identity. He talked about just not wanting patients to google his full name and find his blog, as opposed to preventing people who read his blog from finding out his name.
IIRC some of his most famous early posts ran under his own name! This wasn't ever a real secret.