This doesn't make sense to me. Why would that other member be charged for reporting a threat?
I'm not suggesting they should be, but just following the same logic as your comment.
If you are a comedian working on a joke and write one about a political assassination in your private journal, certainly you can't be charged with communicating a threat, because you did not communicate it. But if a friend/enemy finds your notebook, knows you have no intent to harm, but reports the journal to authorities out of spite anyways, then the friend could be culpable for communicating a false threat, even though the joke is in your handwriting. Maybe they were getting at something like that?
In any case, it was very awkward wording at best for a report from Reuters, it should have been either explained or left out.