Yes, a classic flaw of D&D (and fantasy games in general) is that you have to have baddies to defeat (i.e. kill) and it is easier to handwave it as "it is OK they are all evil anyway". Makes the genocide so much more palatable, don'cha know?

Some of my favorite memories of one D&D campaign was arguing over if goblins had souls and if we had the right to just kill them out of hand. I was arguing the "Yes, they have souls and should be turned to the light" side of the debate, it was quite fun.

Sadly, 4th Edition D&D is back to the "kill monsters, take stuff" vein of games so all goblins, orcs, etc are just evil and need to be killed. *sigh*