An application of the Golden Rule?

So let's rephrase it:

If what you're about to say is intentionally hurtful, and serves no useful or constructive purpose, you should not say it.

Would that be an inarguable statement?

Well, fiirst of all there are probably no inarguable statements, including the one I just made, but putting that aside for now .. :-)

Let me ask you .. does "intentionally hurtful" here imply intent on the part of the deliverer of the statement, or "observed intent" on the part of a third party hearing the deliverer give the statement to the person that the statement is intended for?

It's a subtle point -- which I think is the one you are making, if it's the former then the problem is covered by "treat others as you wish to be treated" (specifically for this case the part that says "I wouldn't like someone to hurt me therefore I will not hurt them") so I don't see the need for a special case statement, of which the above may or may not be an inarguable example of, to cover this scenario.

If it's the latter, and what one says -- unintentionally on the part of the deliverer -- hurts another (I do that all the time, foot-in-mouth syndrome or mouth-engaged before brain syndrome) then there might be a special case statement required for this scenario, but it will along the lines of "really put yourself in the position of the other before you speak".

What do you think?

And yes I agree with the parts of utility and constructiveness (is that a word?) in some scenarios.

Examples, if I shout at my daughter to stop her running into the path of a speeding car, this is constructive (and harsh) indeed. But we have to be careful here, the "constructive" part of the statement is linked to an implied moralistic value, in this case being that "her life should be prolonged for as long as possible" -- and the benefit of her living outweighs the harsh words.

Harder are the times when you might go on a course to learn how to sell something. You may receive constructive criticism that tells you that your behavior needs to change to achieve the goal of selling more. So in this case the implication is that changing the way you behave is a good thing, because you will sell more. After all that is why you came on the class is it not? So then it is up to the individual to decide how he or she interprets the constructive criticism and what he or she does with it.

"Constructive" is a highly variable term I think. One persons "constructive" might be another persons "destructive" might it not?