(I think this is a bit of a distraction from the main thread, but the main issue there was always de-anonymization in the other direction: that patients might Google "Scott Siskind" and find his blog, which might render it difficult to maintain the correct kind of relationship with him as their psychiatrist. He's careful to not accept any readers of his blog as patients.)
Well, he signed up for exactly that outcome with full knowledge it could happen.
Outing a psychiatrist's internet ramblings to his patients is not high on my list of journalistic crimes.
The same can be said for any other instance of deanonymization, and yet we do not thereby (by default) absolve everyone who deanonymizes someone else against their will. Was Scott perfectly careful? No. Was this something that harmed him in straightforward and predictable ways, and done against his wishes? Yes. Was there a trade-off that made it worth it? Not a question that Cade Metz has seen fit to answer publicly.