My corporate partners often do nondisclosure agreements so that parties that are contemplating a business transaction can do their due diligence but the financial info will remain confidential. Nothing illegal about that.
This entire issue has been made up Trumphating politicians and mediots. These Manhattan lawyers know all this but say nothing because they too are Trumphaters and they know at least half the country will believe this Bravo Sierra.
Does any of your extensive experience involve Orange Man Bad and a man who wants to go down in history?