Gygax referenced that saying in its original context of "massacring children." He even name-checked the real historical colonel who used it when ordering a massacre of women, children, and elders. He was explaining why it's cool for a paladin to kill baby orcs.
There's really no way to defend that. I tried starting from the proposition that Gygax was a wargamer who enjoyed strategizing toward the optimal path to victory, and so he wanted to have "bad guy" races where you didn't have to consider the moral dimension of your strategy. And then I get to the bit where Gygax (a noted history buff) brings in an actual historical atrocity, and he clearly knows what he is talking about, and he cites it as support for his argument, and there's just no place you can go from there other than "Holy smokes, Gary, what the hell were you thinking?"
I haven't listened to the podcast, so perhaps Tim Kask was totally ignorant of what Gygax said and the context he said it in, and he assumed the same thing you did (it's just a way to say you should take care of problems early). I hope so, for his sake, because otherwise... yeah.