Not sure how legal any of this would have been, or how legal what happened was, seeing as how neither Argentina nor Britain was in a declared state of war when they were sinking each others ships and killing each other's servicemen...
That was my point also, naval law can not be applied partially. Following logic that it was war, London could nuke Buenos Aires.
Britain had every right to declare war on Argentina, but did not bother.
I agree that states act in their own interest. So why accuse Israel of selling arms to anyone? There was no international arms embargo against Argentina. States act thuggish if they break the laws, treaties and agreements they ratified. It was ok for France to try to prevent Argentina from purchasing Exocet from third countries. But it was thuggish to provide data of Exocet sold to Argentina to Britain.