It was a weird situation because I think if he had said "don't do this full stop" then it would have been clear. But he tried to put on bravado and an attitude of "I don't care" when he clearly did. People tried to talk sense to him behind the scenes but his attitude made it harder to tackle the problem.

There are no rules against posting external links to things like KF theads that contain dox, as far as I know. I agree that it is sharing information deliberately in order to cause someone distress but it's the Internet and he doxed himself in a dumb way - he needed to suck it up or insist more was done to prevent the information being spread, or do anything other than what he did do, really.