Civilians who live with soldiers are legit targets. Civilians who cook for soldiers live with soldiers. There is an old Chinese saying. Dao Jian Bu Zhang Yan. Swords and arrows don't grow eyes. Bombs will kill civilians if civilians live with soldiers. And that is perfectly legit.
Nope, if you enter an Army base, sneak into an appartment where there is a civilian woman preparing rice, and cut her throat, you have committed a war crime.
If she attacks you with a knife, she becomes a legit target.
If You fire an artillery shell at a canteen filled with soldiers, and kills a woman cooking rice inside the canteen, you have not committed a war crime.
You are confusing killing with targetting. They have different meaning.
Targetting a civilian means that you identify someone as a civilian, and decide to kill the civilian.
Attacking a military target is not targetting a civilian, even if you happen till kill any civilian present in the military target.
Again, show where in the Geneva Convention there is support for your view?
Your own personal opinion has zero value.