Those girls live in Kiryat Shmona near the northern border and are under missile attack from the terrorists. I would say this battle is a little more personal for them, wouldn't you?
Those kids are in the path of numerous randomly fired rockets intended to hit civilians. The Muslims want to kill these girls. They could be killed any minute. Maybe they are dead right now. If the girls were a few years older, they would be in the military trying to defend their little sisters and brothers. I see no problem with letting them get involved.