Is it permissible to kill the enemy's children in order to protect the lives of one's own children?

80% of the Germans are against how Israel Operates in Gaza
Julian Reichelt — from german to english using google:
It is my deep and unshakable conviction that the overwhelming majority
of German citizens are mistaken. And I would like to explain why. I
would also like to address, above all, the unspeakable: children killed
in the bombing war. It is always this question that hangs, leaden and
ultimately unanswerable, over every war against barbarism: How many
humanly unbearable sacrifices, how many dead children, can one accept?
…
Is it permissible to kill the enemy's children in order to protect the
lives of one's own children?
…
The further away you live from these questions and the more securely
your children sleep, the easier it is to answer them with moral
superiority. The closer you get to these questions, to the hail of
rockets, the terror, and the barbaric attacks, the closer you come to a
simple human truth, a fact of our existence, a brutal logic of our love,
and the archaic core of our survival drive and protective instinct: We
would all be only too willing to inflict suffering on others in order to
protect our own children from harm. The more inhumane and merciless our
enemy, the greater our willingness. The more urgent and immediate the
danger before us, the harder we would strike. All of our morality only
functions without threat. Each of us would be willing to torture if it
meant we could find the bomb on our children's school bus, no matter how
slim the chance.
https://www.nius.de/kommentar/news/kampf-gegen-hamas-und-islamismus-wir-unterwerfen-uns-israel-nicht/0180807c-de4d-4f70-8ad9-64e7bbbe4572