I would like to imagine that morals and ethics are more concrete than that; yet, I do understand that many in society do not have a solid grounding in the philosophical fundamentals of their moral stances.
Terrorists are absolutely not within the confines of the Geneva. They violate several of the provisions. But, they are within the confines of the UN and thus "international law."
As to this point, "They are simply being 'worked' for further intel."
Would it be justified for the US to remotely install and utilize advanced malware placed on foreign computers and networks to extract information?
The idea that our laws protect our people is quite true. But in a very broad sense, our laws reflect our morals. Therefore, in a broad sense, if we apply our morality to the situation, we should also apply our law.
If we do not, we may be lawful, in that our law doesn't apply or specifically state, but we aren't exactly being moral, by our own standards.
As to above quote, I just don't see morals and ethics to be some innate quality possessed by all. Certainly the morals and ethics of one individual differs. Certainly the morals and ethics of one country to another differ, as well.