The information may be publicly available, but it is not typically put on public view. Only people who look for the information would see it.
What Castro did was to publicize the information, along with defaming the people whose names he publicized. It is obvious he was inviting people to harass and attack those whose names he publicized.
He most certainly did commit an ethics violation. Inciting violence against people is highly unethical.
People used to post that stuff on FR all the time. Every time a celebrity piece was on there was a cadre that put their donation info in the thread. Was that incitement to violence?