Lack of belief in god is a rational position. There is no evidence to support the existence of any god.<quoted text>
Lack of belief in God is a moral position as that belief dictates human moral reactions to the idea of God...
Why would atheistic secular humanism claim an absolute moral standard as you stated about genocide?
Secular humanism is not atheistic. It just rejects religious dogma. You can believe in any number of gods and still be a secular humanist. And it doesn't claim any moral absolutes. I don't think such a thing exists.