List these other “atheist reasonings” you keep touting and cowering under.
Let’s see how they stand.
You are still missing the point, which again is not that atheists cannot arrive at moral conclusions, but that atheism cannot point to an accepted transcendent moral standard which defines morality - which evolutionary science does not - thus this being what the atheists position lines up with, even interpretively, or by which they are judged by. Lacking this, each atheist can argue that their reasoning is superior to yours in opposing you on such an issue as fornication. I am sorry if this was not made clear enough to you.
Moreover, i could provide some examples of those who disagree with you, but you have not specified what you mean by fornication, such as do you reject any and all premarital sex and all homosexual relations, and exclude gay marriage?