Someone once wrote an “interpretation” of diplomatic language: Example: “We had frank discussions” means “we have our thumbs on their jugular.”
Why is diplomacy so full of bland speech? Even hypocrisy? Answer: A frank assessment may shut down fruitful negotiations over delicate issues. Open agreements openly arrived at is an ideal that if literally carried out may result in zero agreements. Talks away from public scrutiny may be necessary. Sometimes public announcements in which news is limited to those bland statements allow meaningful give and take to reach a compromise.
In negotiations when both sides want ninety percent, each will have to settle for less if they want to conclude an agreement. Naming your opponent an irresponsible egomaniac is unlikely to wring concessions from him. Bland speech may keep the negotiations going until a meaningful compromise is reached.
Compromise? You are so reasonable, A-G!