To answer both you and c4cat
Here's how it works. The israelis use what is known as counterbattery radar to track the incoming rockets and from their trajectories determine the position from which they were fired.
The next step is to attack that position either by artillery or airstrike in order to eliminate the source of the incoming rockets. The purpose is to stop the rockets, not kill people by the truckload. This is regarded in military circles as a defensive measure
hamas knows this. Israel has followed this model for some time.
If hamas either fired their rockets from uninhabited areas or evacuated non combatants before firing there would not be "civilian casualties.
Instead there always are and they always seem to include children.
The only logical conclusions are : 1. The israelies can't shoot for shirt, or, 2. hamas deliberately fire from places that will result in "civilian" casualties when the counter battery fire arrives. This gives them ammunition to scream "victim" and gain international support for them and condemnation for israel.
There is much argument as to which of these two is actually happening.
The fact that israel has installed the hugely expensive "Iron Dome" anti missile/rocket defence system when they could have just bought more shells to fire at Gaza speaks volumes.
Short version, the children fired no rockets. A great many people think they are kept close to the firing positions as a kind of human shield. The israeli practice of counter battery fire is so well known that if hamas had any intention of protecting peacefull palestinians they would shoot from where there were none.
Or maybe the israelis just cant shoot straight.