If it was game in a modern campaign setting and the PCs stormed the offices of Evil Corp TM, were stopped by security and murdered every single one of them that shot at them, I don't think me or most people will have a problem with that. Presumably every security guard that tried to stop the PCs were Humans and had families too. But security guards like that get killed all the time in action movies, and it's expected that PCs kill them too.
The difference is that nobody, absolutely nobody, who writes that scene in that action movie then writes their heroes confronting the grieving families of the people they killed-- which is something that a certain kind of juvenile DM absolutely gets off on-- and the audience of the action movie doesn't expect an angelic pat on the head for being objectively morally correct when cheering on the right heroes.
You can write a story about Good triumphing over Evil, and you can write a story about real-life actions having real-life consequences, but you can't write them both at the same time-- and you can't "keep things simple" and keep introducing moral complications at the same time. As soon as you introduce the question of killing orc babies, you cannot stop the inexorable slide toward questioning the wholesale killing of their fathers. And the problem is... a lot of people keep saying that they want one of these games or the other, but then they keep trying to shoehorn the other style of gameplay into it.
You do know orcs have had playable stats since Basic, right?
Like, do we really want to have the argument about this again when their legacy in the game has been "You can play as these" and they have a legacy longer than gnomes? Because, Orcs of Thar was 1988, Top Ballista (I'm 90% sure that's the first playable gnome stats came from) was 1989
and like, I'm a gnome fan and I'm bringing this up.
Gnomes were a playable race in the AD&D Player's Handbook, 1978; I think you're probably right about Top Ballista being their debut in Basic D&D. Orcs of Thar offered the first playable orcs (and trolls) for Basic in 1989, Complete Book of Humanoids added a bunch of common humanoids to AD&D (2e) in 1993.
Ten years before World of Warcraft. But since when have facts ever made a difference in this argument?