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.
I think your argument bites itself. "most importantly, they are humanoid." You seem to agree that people of any race are worth the same. While you are willing to expand the set of entities to whom your system of morals applies beyond tribe and race to all humanoids you draw the border at "most importantly humanoid". So it does not apply to sentient beings that are not humanoid. Is "can a human create viable offspring with it" a good basis for a system of morals?
If current western morals are to be normative then why is "racism" evil but "speciesism" is not?
"Thing is, we do want the contemporary morals implemented"
I do not want that at all. It's all arbitrary and rooted in cultures that simply do not exist in the forgotten realms.
I see your point, but this is not what my personal view is. Since I am convinced in the real world that every man is created equal I put that belief into the game and extend it to every being that has a comparable social structure, regardless of the humanoid thing (which in itself is quite a variety, like anything walking upright and having two legs can be considered humanoid so bird people, lizard people, inanimate machines and undead). Many players do the same, but draw the line at the humanoid thing. The Rachni from Mass Effect are a good example. For me there was no other way than helping an insectoid race become a thing again. Many other players ( I think there were stats on that) drew the line there. So I deduced that this would be the same here, gobbos are humanoid so most players are inclined to extend the morals to them as well.
It gets really interesting when developers put sentient creatures into their game that are either benign or have a point, but are appaling to look at and/or generally considered hostile. That is where peoples' morals really grind their gears. It does not mean that deciding against, say, a nice phase spider is wrong or right, but is contemporary moral either way.
And I still think that all games are basically rooted into the western moral code. If they are not, or if parts of it are not (Caesar's Legion comes to mind in Fallout: NV) there are serious repercussions attached. And even they abide to certain principles not unknown to us, although they are the clearly evil path. Stealing for example is not a thing, and neither is the killing of infants (which also wasn't in the game). If we take the BG as an example over the last 20 years it is rather clear it was modeled after the real world. Keep in mind morals does not necessarily mean equal to culture, but any gender can do anything and anyone can also date anyone, there are gobbo followers, drow can seemingly walk freely on the surface (and get a charisma bonus). Quite a few things even changed over the last two decades. There are still some antiquated social structures, but way more ways to get out of them and many stories/quests evolve around breaking those up, like dethroning that lord that treats his people bad and such.
Now a game that is not at all rooted in these traditionally narrow set of morals, would need to be totally reinvented and probably disconnected from the human race, too. And of course when you break out of it, you will need to add all the added repercussions. Like I said before, if you are known to be the happy baby cat killer, you are not going to be invited to tea very often. If you hunt gobbo kids for sport, then companions should leave, spread the word and cut you out of a lot of content. Some might even secretly like it, but that does not mean these people would like to openly be seen with the "monster of the goblin village". If nothing like this is the case then the addition is moot and without benefit.
I did not expect anything from the title, but it actually made me think about that sort of stuff. Hence I keep on discussing.