"Why can't we kill children?"
Because the game would be banned pretty much everywhere.
Without sharing more spoilers from what I saw in Ghent, I don't think that's the reason
As fylimar says, I think it's worth waiting and seeing if there are more options for interacting with the tiefling kids in the full release.
Though I think the tiefling kids are great and in a lot of my playthroughs happily hand over cash to help Mol set up her guild in Baldur's Gate. I do enjoy it when my characters pass the checks to get the better of them and earn their respect, but am also fine when they don't and my character ends up looking a bit of a wally (ie a silly an inept person, as I suspect that's pretty local slang!). I'm okay with my PC not being the epitome of cool all the time. Not that I think killing or even corporally punishing kids for going too far would be at all cool, either! Still, I do agree the game should give us as many options to roleplay our characters as possible, even if some of those options I personally am unlikely to ever take.
