Exposing identities is indeed a very wide spectrum, ranging from identities of sentenced terrorists (nobody'd question that, usually the legalities revolve arou

Exposing identities is indeed a very wide spectrum, ranging from identities of sentenced terrorists (nobody'd question that, usually the legalities revolve around the concept of "public figure" which greenlights a lot of publication that would not be allowed about just any random person) on one extreme to identities of people who were found voting for X in an illegal interception of mail ballots on the other extreme. It doesn't really matter where exactly Apple would draw a line, from absurd extremes like "you are free to talk about Roman officials infamous for sentencing innocents to the cross, but please do so without mentioning PII" when someone types in Pontius Pilate, to pragmatic, maybe even lazy "don't use the channel for illegal communications (but we can't really police them)". But they should at least try to be somewhat consistent about it and, even more importantly (but much easier!), by no means require secrecy. A secrecy requirement is just lame and reeks of foul play, horribly.