I think this thread could only be improved by a derailment. Killing children isn't my hang up per se, it's that even in D&D I think most people would consider it a particularly heinous act. Like the child 'predator' you meet in prison in one of the previous games. I've killed the goblin children while rescuing Halsin before because they're running away to warn the entire camp, I've seen a spit with human and dwarf bits on it, I've spoken to others before who said they'd kill me in my sleep and they take pleasure in being cruel to animals. Couple that with my preexisting knowledge of goblins as cruel venal creatures at the bottom of the goblinoid totem pole, and I can cobble together a good enough reason for most of my characters to kill them.
As opposed to what I know about the Tiefling children. They're scared. Some are being trained to fight, which made me dislike the adults a little, but which I interpreted as an act of desperation. There's also a group of moppets who steal trinkets from everyone to survive, and want to steal an idol to stop a ritual that will force them into the wilderness, where they will most likely die. So another act of desperation. Me, the player, doesn't have a preconceived notion about a Tiefling's infernal heritage, and seemingly neither does my character, at least I can't recall it coming up. So that angle doesn't work. So in order for my character to kill these children without compunction, he'll need either a compelling reason from the goblin camp, or he needs to be a character who is just that evil. Being a character who is that evil is fine to me but I would appreciate some kind of build-up to it, a conversation here or there about what kind of person I am to do such a thing.