That is why, even in war, we treat the enemy respectfully. Because we know that there will be a time when we are not at war. And getting to a time of peace happens quicker if there is mutual trust and respect... even though we are doing the best to kill each other.
These people are ruled by savagery and cannot be trusted.
And even that hasn't brought respect from our enemies, or victory over them for decades now. When the government decided to put lawyers on the battlefield to teach our military how not to offend their enemies, this country lost the ability to win any war, using whatever means possible. I doubt Harry Truman sat around a table with a bunch of lawyers before he decided to offend Japan by dropping the bombs on Hiroshima and Nagasaki.