This is a great, honorable young man, and his targets are evil. But no human is less than human, we are all children of God and all sinners, as our mutual faith teaches. Whether aborted children, the ill or infirm, the incapacitated, like Teri Schiavo, or even these evil terrorist scum, there are no sub-humans - there is no life unworthy of life. There are humans whose killing is wholly and fully justifed, as in this case, and I understand the emotional reason to speak of sub-humans, but it is far better to think of them as the worst of human sinners whom , through the intervention of this remarkable young man, God has seen fit to be removed.
You're a better person than I. I still can't see them as anything more than verminous slime.
I look at it this way. Some people long ago reneged on their membership dues and violated the rules of the human race and thus have had their membership revoked. That's how I look at these nihilistic beasts.
Nevertheless, I honor and appreciate your high road approach.