But D&D has not had a very consistent view of them even in the earliest days. Orcs were nightmare creatures, but also creatures of flesh and blood who birth and raise children. They aren't undead or unnatural beings, nor are they beasts with no capacity to think or reason. They were evil because the Monster Manual said they were evil, and the excuses for why (evil society, dominated by evil gods) came later.
I don't want to litigate the orcs debate again, because I still accept the notion that most orcs you would meet are evil is a valid play style. My concern though is that then being evil justified a lot of actions we would consider heinous war crimes. Even if they are creatures bent towards evil, they are living natural creatures and that alone should warrant certain rules of engagement. The idea that you can barge into their homes, kill their families and take their stuff because they are evil just seems so... Repellent when you consider ** gestures vaguely at several world conflicts **.
So I think KotB, even keeping the idea that the humanoids of the Caves are majority evil-intended and malicious to the keep, should be redone to remove the overt colonial elements from the story. Several people have suggested good alternatives to why the Caves would have various humanoids and not their families. (A staging ground for an invading army, gathered by the Temple of Chaos, is perfect in its simplicity).