Because private conversations with world leaders are off the record?
Neither the public nor the media has a rjght to see them. Period.
Nothing conspiratorial or extraordinary about it. Just normal state protocol.
And also not all that unusual. Plus, you can't leak what you don't have.
Nothing like some notes of a recent meeting to reinforce (or correct) one's memory of the conversation. Nothing odd about that. Nothing odd about not keeping it for the long term, either.
"[T]he Court holds that [Massachusetts law] may not constitutionally prohibit the secret audio recording of government officials..."