No one is saying a church is “public property”.
The church invited a public official to speak and invited the public in. And this member of the public recorded the public official speaking at a public event.
In the future, hold a private event, and send out RSVPs, and clearly state that no recording is allowed.
What public official was invited? The only person I’ve heard about is John Kitzhaber.
I don’t think that candidates are “public officials” until elected. Since Governor Kitzhaber is no longer in office, I would also say that he wouldn’t be considered a “public official” either.