Diaries...

The diaries containing Charles's views on the 1997 handover of the British colony of Hong Kong to China were copied by a former member of his staff and circulated to newspapers.
Charles is suing in the High Court for breach of copyright and confidentiality

Hm.. not just Charles... everyone really.. they're afraid that their mum/sis/bro will read their diaries... So why do they write it?
Cant they just keep their own personal private confidential thoughts head? Why do they have to express it in writing at the risk of being read by others if they don't want anyone else to know?