I like alignment

[Sucrose]

Do you even realize what it is you are saying?

Why, yes, I do. Thank you for asking.

If someone thinks of human life as worthless, it does not automatically mean they are willing to kill humans with no compunctions. One does not necessarily follow the other.

Incorrect. If you have compunctions, prickings of conscience, then that means that you subconsciously realize that these lives do have value. If you honestly thought that there were nothing about humans that was worthwhile, then it wouldn't bother you for them to be destroyed. It would be like taking an antibiotic to kill an infection.

An elf can think of human life as worthless without having any desire to murder an entire city of humans, and be able to recognize such an act as monstrous. It's entirely possible that coming face-to-face with such a situation would cause that elf to reevaluate his perceptions of humans, even. (It also might not affect him at all.)

People do not generally examine their own beliefs in detail--they are just there, and we act on them. D&D characters are no different.

I never said that they would have a desire to do it. It simply wouldn't factor into their moral considerations, since the human lives are valueless. You can think that you believe a group's lives have no value, and still be horrified by their extermination, but that just means that you didn't actually believe that. If you did, it would not affect you.

It is possible to think that you believe human lives are valueless, and still, despite your bigoted attitude, be a good enough person to not be considered Evil. If you don't allow your bigotry to affect your dealings with the humans all that much, you might even manage to be Good.

But actually believing that said lives are valueless is simply sociopathy. Which is evil enough to overshadow any other personality traits.