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.
I guess Metz would have a lot of sympathy for someone drawing the heat of the entire internet, and even powerful VCs, by doing something that many people think is destructive "on principle".