When someone joined The Blood Cult with the sole purpose of getting a temple list in order to target their attacks, you guys were perfectly fine with this and kept saying how religion isn't a secret and is public by nature.
I don't see why it wasn't true with that griefer but would apply for archival reasons.
technically.. temple location is not much of a secret. all you need is a noble friend in every realm looking up all their regions. (obviously you have to visit rogue regions)