I don’t think you understood the underpinning reasoning in the points discussed in my previous post. Refute the logic, or give up. Weasel words referring to some “atheists” or some “christians” and their “arguments” is meaningless in this discussion when you haven’t highlighted or brought forth any contradictions in the points made, using the arguments from the sources you mention (the “some atheists”, etc.).
Despite whatever you may think, the fact is that the issue never was whether you could support your position that fornication was wrong, but how atheism consistently determining sin, that without a transcendent moral standard that defines sin, in atheism your argument is only that, as another atheist can disagree with you that fornication is wrong, or gay marriage, etc.
Atheism is like a country without a substantive universal constitution, and under it what seems reasonable to Mao or atheistic Communism can just be easily justified as like Islamic conquests can.
Refute the logic, or give up.