What is Ethical is not objective. It is very subjective. Context, context and context.

A policy by it's very nature is ethical. Policy is doing what you believe to be right = thus ethical = thus Clausewitz never discusses it. He just assumes you have an an "ethical policy." Who would not? Wars are caused by different policies, thus different ethics. Ethics is usually politics. Is a free-market "Ethical"?

Al Qieda is a highly ethical organisation. They just have different ethics, and Polices un-acceptable to most here.

Ethics, morality and legality, are entirely different subjects and only loosely related.

Intelligence operations are guided by policy and legality - NOT Ethics!
Intelligence operations often require you to gain trust and then abuse that trust. Ethical? Who cares! What is the Policy? Is it legal?