Good and evil have to do with life and the maintenance thereof. There is no such thing, for instance, as an evil rock.
-- and they'd be so even if you or I had never been born.
Not true.
The concepts of good and evil are relevant only to living things; they have no meaning whatsoever -- they are not "so -- to non-living (unborn or dead) things.
If they are objective, they are true regardless of whether there are living things to recognize them. That's what "objective" means.
The concepts of good and evil are relevant only to living things; they have no meaning whatsoever -- they are not "so -- to non-living (unborn or dead) things.
You've missed the point entirely. You and I are both alive. Would your tenets still apply to me, regardless of whether or not you were born?
Because Rand's tenets are allegedly objective, you are required to answer "yes" to that question. Which says that the origins of "good" and "evil" is not your reason. Instead, those concepts exist independently of your existence, or my existence. In fact, if they are objectively true, they would exist even if there weren't any human beings.
And once again we run against the rocks of objective reality. Objective reality is simply chock-full of things that we accept as natural among animals, but consider "evil" when humans do them to each other. Ayn Rand's objectivism is completely unable to account for this difference, because it specifically requires us to base our judgements on what we can observe.
Your concepts of what constitutes "evil" cannot be found in nature. Thus, if you want to call it evil when a salamikaze stabs his daughter to death, you've got to look outside of nature for the reason. (Social Darwinism could probably justify it on eugenic terms.)