Trust requires that someone's personal remarks not be circulated without permission. For example, if a friend shares a family difficulty in confidence, repeating it as gossip violates the purpose of that trust.
Confidentiality, however, must not be used to assist serious injustice. The fuller report discusses exceptions involving unlawful killing, forbidden conduct, and the unlawful taking of property. The underlying concern is to protect trust without sacrificing the basic rights of others.
If people seriously plan to attack someone or take their property, it may be appropriate to pass the necessary information to a responsible person able to prevent the harm. That is different from publicizing private information carelessly.
Principle: maintain ordinary confidences; in the presence of a serious threat, take proportionate, responsible action and share only what is necessary.