Where do School Shootings Come From?

Is it because we have people who agree things like this are okay?

Deuteronomy 2
32 When Sihon and all his army came out to meet us in battle at Jahaz, 33 the Lord our God delivered him over to us and we struck him down, together with his sons and his whole army. 34 At that time we took all his towns and completely destroyed[c] them—men, women and children. We left no survivors.

Deuteronomy 3
3 So the Lord our God also gave into our hands Og king of Bashan and all his army. We struck them down, leaving no survivors. 4 At that time we took all his cities. There was not one of the sixty cities that we did not take from them—the whole region of Argob, Og’s kingdom in Bashan. 5 All these cities were fortified with high walls and with gates and bars, and there were also a great many unwalled villages. 6 We completely destroyed[a] them, as we had done with Sihon king of Heshbon, destroying[b] every city—men, women and children.

Judges 21
10 So the assembly sent twelve thousand fighting men with instructions to go to Jabesh Gilead and put to the sword those living there, including the women and children.

Ezekiel 9
5 As I listened, he said to the others, “Follow him through the city and kill, without showing pity or compassion. 6 Slaughter the old men, the young men and women, the mothers and children, but do not touch anyone who has the mark. Begin at my sanctuary.” So they began with the old men who were in front of the temple.

And in Joshua 6, at Jericho:
20 When the trumpets sounded, the army shouted, and at the sound of the trumpet, when the men gave a loud shout, the wall collapsed; so everyone charged straight in, and they took the city. 21 They devoted the city to the Lord and destroyed with the sword every living thing in it—men and women, young and old, cattle, sheep and donkeys.