When the lives of a group are threatened by another:
1. The role of the image of God is to preserve human life.
2. Human life must be seen in terms of the image, and therefore, whoever shuns that role cannot be seen as someone who is as human as the one who accepts it.
3. Not everyone, therefore, has an equal right to live, as one group has evidenced itself as shunning its human role to preserve human life as the images of God.
4. The group that is being threatened, although they may not be completely receiving their role as the image, still evidence some of that role by not being the aggressors in murderous acts.
5. The group that is threatening human life is shunning the role of the image.
6. The group that is being threatened, therefore, is more human, and subsequently has more of a right to live in this situation, than the group that is doing the threatening.
7. The children of each group are not taking any actions in and of themselves.
8. They belong to one of each group, and as such, either belong to a group that is more or less human than the other group, having more of less rights to live because of the actions of their group.
9. The children of a group are seen as part of that group, whether they make the decisions or have the same ability to take action or not. As the child is represented by his family, he is also represented by his group. He, therefore, shares in the rewards or punishments that the group acquires by its actions.
10. The question becomes whether there is a higher probability for the children in the murderous group to become murderers themselves in the future and children in the threatened group to become preservers of human life more than they.
11. The jihadist atmosphere of the area in which this group resides makes it a higher probability that the children will grow up to become more like their group in their murderous mentality.
12. It is, therefore, regrettable that any life, even the ones that are not living as the human beings they were purposed to be in creation, would have to be taken; but for the sake of doing our own jobs as human beings who, as the images of God, must defend and preserve human life, we must make the decision to destroy what evidences itself as lesser humanity in order to preserve what is greater humanity. This is essentially what people mean by killing the guilty in self defense in order to protect the innocent.
Where did I get these propositions: The Scripture. Our concepts of guilty and innocent are based on Scriptural principles concerning humanity, and what humanity is meant to be and purposed to do in the world as humanity. It is a creation ethic. Hence, as the creation mandate is related after the flood to be fruitful and multiply and fill up the earth (i.e., be co-creators in the world), the command to destroy chaotic agents/murderers is also given along with it (i.e., to be a co-creator and preserve human life means being a destroyer of destroyers as well). Unfortunately, sometimes it is inevitable to have to destroy entire groups of destroyers when there is an imminent threat as the one above. Hence, the creation ethic is a good that destroys even children of destroyers when called for in the exodus from Egypt and the Canaanite conquest.
Conversely, if I were to attempt to base my decision on our current ethic that sees all people as equally worthy of life, regardless of the course they have chosen to take in the world, or not see children as identified as one with the people of either group, I would end up being in an unsolvable conundrum, and just have to arbitrarily choose, based on nationality or ethnicity, who would survive (an "us" versus "them" or some other criteria). In the current view, I would essentially be in the wrong either way. Hence, we get a lot of arguments condemning collateral damage in war, the death penalty as inconsistent with a pro-life stance, condemnation of the Canaanite Conquest, etc.