Haha. That guy or his lawyers thinks that writing "Private and...

Haha. That guy or his lawyers thinks that writing "Private and Confidential" on a legal letter just magically makes it that. Lol.
Unless you have a previously signed contract agreement, or you are certain government agencies, then nothing is legally binding re confidentiality.
Of course, that doesn't stop a tit for tat spat, that might embarrass, but you get my drift. I pays to not be an idiot if you're going to put something down on "paper".