Bacon Bits
Legend
He cites real life.He quotes a phrase historically used to justify the slaughter of noncombatant women & children, and references a specific person who used it for that purpose.
So what? He's allowed to use rhetoric in his arguments.
He cites real life to show that, historically, "justice" was often brutal and swift. That "an eye for an eye" is quite a common standard of law. That it existed as such in our world and may exist as such in a fantasy world, too. Indeed, Gary doesn't mention it, but when the Bible talks about "an eye for an eye and a tooth for a tooth" it's quite often interpreted as a call for an appropriate and measured punishment, since at the time the punishment for a crime was often, by law, much more severe than the crime itself!
As for the Chivington quote, Gygax himself points out that lots of people have used the same logic to justify massacres. And the saying is true in it's most literal interpretation. If X is always evil, then it's good to destroy all X. You want to say that because the bolded part isn't always true and generates really unpleasant side effects when applied to races of people, that the italicized half isn't a logical conclusion. That's balderdash! We're injecting our own premises into that argument. Ideas about how we think because that's how we operate. And that's how we want whole peoples to be treated, because doing otherwise reminds us of all the horrors of our world when that didn't happen. It reminds us of what made us monsters. We have good reasons to want to move away from that, but that's still how it originally worked.
We're not really extending the same courtesy to everything. We still have "always Evil" in D&D. Demons. Or devils. Or undead. Or mind flayers. Or beholders. Or green hags. Or chimera. Or efreet. Or red dragons. Take any of those and plug them into "If X is always evil, then it's good to destroy all X." You've probably played more than one PC that would agree with those statements. It's less problematic to have a game where it's never used as a label for whole races of people. But it's not not problematic for sapient creatures of a given class to have identical and basically immutable morality... but only as long as they're inhuman.
The truth is that the game needs monsters, and monsters make us uncomfortable. Because we know human monsters are real. So we're going to be very careful to not make the game's actual monsters too much like us. This hair is a lot finer than people think it is.
Like you look at the statements made about gnolls... I really don't think that's an improvement. "Oh, we'll just categorize the whole race of peoples into fiends and now it's okay." Like a whole race of "always Evil" humanoids is bad, but I don't think a whole type of fiend being "always Evil" is really a significant improvement. It's still eliminating agency and free will and using language reminiscent of colonialism and genocide when you describe them. There's nothing stopping fiends from having a culture or a society.
At some point you have to just... draw an arbitrary line and say, "Eh, that's good enough. I'm okay with that. We know what we mean, and it's just a game. Let's roll some dice and kill some monsters and take their stuff and call ourselves heroes!" I think the new line is better than the old line, but we're still just drawing that arbitrary line.