In fact, these are obvious things, but this does not cancel the double standards - the children of some rational beings can be killed because they are evil, while the children of others hypocritically cannot, because they are "good". Why can't I kill those nasty tieflings who robbed me? Stealing from the main character is as much a motive to attack as goblin children throwing stones at a bear.
Or maybe I'm playing as a complete scumbag and want to personally execute Arabella to show the shadow druids what a bastard I am. Why not? Why can't you kill good children, but you can kill bad children in this game?
Although a gang of teenage tiefling thieves can't be called "good", they can't be dealt with just because of their race...
Either make everyone immortal, or give the ability to kill everyone. Both options are good, I don't mind if the goblin kids just run away with 1 hp
I completely agree with you on this. I never liked unkillable NPCs. If you want to have children running around to make your world more believable, then you need to take the risk that someone might kill them all. My answer would be not to give them immunity, but to make it pointless. 0 Exp and no loot on any bodies of a character under age. Repercussions would be against your reputation. Maybe a forced expulsion from the Grove, but at least one merchant tells you what a great job you did and that they will be happy to work with you out of the cave that you find that druid in. Making people unkillable is lazy. Making consequences for killing people you don't want killed is harder.