Clauses with this defect are unenforceable in a court of law. This kind of generality intimidates staff because they are left in the dark as to what they can say - so they say nothing. A legitimate confidentiality clauses is specific in character. It presents confidentiality as an absolute. It does not balance it against other considerations.
Absolute confidentiality is secrecy.
Proper respect for confidentiality is only always a presumption in favour of non-disclosure i.e. good reasons have to be given for disclosing. But there are always such possible reasons. In most general terms the public interest may make a breach of confidentiality legitimate. A legitimate clause spells out the other side of the balance. It immediately associates discipline and dismissal with breach of confidentiality.