[NeedMoreTea]

Sure, and a hundred or more years later the family of the author, or relatives of the recipient can decide to release the family letters or telegram from WW1 or the US Civil War etc. That delay, usually at least until the correspondents have died, is important. The affair, the less than ideal belief, and all that other imperfect demonstration of humanity can no longer hurt or embarrass. It ceases to be private and personal and moves into the historic.

Releasing whilst the probably famous sender is alive is most often in the realms of to do damage, simply tasteless or paid for revelations in the gutter press.