Somehow I think the villian is more evil if they kill random NPCs and unnamed townspeople, because they are 'innocent' people. What I mean by that, is that the PCs are trying to kill said villian, so, in self-defence, they would kill the PC. But the NPCs never did anything against the villain, so it seems slightly more evil to kill innocent NPCs than slightly less innocent PCs.

Remember, the above paragraph is an OPINION. Not FACT.