Sure, could be, but even then the OP is correct in calling this out as a bug. Still I suppose you are talking about Tiefling kids not being attackable and not Goblin kids being attackable. The problem with having that option is that, while the game wanting to represent contemporary moral standards and also include being able to open a wide variety of choices, they do not offer the corresponding consequences. Does the killing of the Gobbo kids remove the option to side with the goblin camp? It should. It should also have several other consequences like companions leaving, quest givers not giving quests anymore, certain factions or NPCs being hostile on sight, restricting certain traders, increase trading prices and so forth. So it would reflect the consequences of the real world, they are trying to represent in a fantasy setting.
Contemporary moral standards don't apply in a fantasy setting. To most people in Faerûn goblins are nothing more than dangerous pests, so most people would be ok with anyone doing pest control. Traders/merchants and travelers would more than likely be grateful that you've made the roads a little safer to travel. And let's be honest ... if you're slaughtering them, you're unlikely to want to forge an alliance with them anyway.
Oh, they do. That is why there were no same-sex romances in BG1+2 (romance was even race-restricted in some cases), but they were in SoD and the Enhanced Editions. They've also been in any RPG of the last decade. And since the last three years we have seen more and more representation, with rather "polarizing" outcomes. Like Corwyn in SoD, who in a half-sentence, told you her lifestory and the internet went ablaze. I believe you can romance anyone regardless of race/class/gender in Baldur's Gate III, just like you can about anywhere in the Western World. Thing is, we do want the contemporary morals implemented, and some things haven't changed in thousands of years, regardless if it is a fantasy setting or set in the "real world". The killing of infants, like murder in general or stealing is one of them. That also extends to animals or, vermin. Goblins are on a higher tier, because they are an intelligent people with culture and language and, most importantly, they are humanoid. So you would have a hard time drowning a baby cat already, but a much harder time killing an infant that can talk back and resembles something you are very familiar with. The reason we see it a lot in games and the demand for it, is because of reloading and no consequences whatsoever attached to it. That is why it is a double-standard to have certain actions, yet not the repercussions. That is why having amoral decisions in general in games is tendencially futile and solely there for the "hurhur, I just wiped out a village"-effect. So like GTA, where to whole world is curiously devoid of children.