Well the law of every civilised nation on the planet, including the one you currently live in, says you're wrong, Sam. Rights are just that, rights. They are of universal application. We don't get to pick and choose when we apply our freedoms, because if we did they wouldn't be freedoms at all.
Those at the COBRA meeting that sanctioned the kill didn't agree at all. Again, if he'd had some amazing change of heart and had come home do you think he would have been executed without trial? He was an illegal combatant in a war zone and he got what was coming to him. But we don't stoop to their level by saying that fundamental freedoms and rights can be ignored when everybody feels angry enough.
Congrats on the engagement BTW. Really pleased for you.