False analogy. Prohibition was trying to make a moral absolute (no use of alcohol) out of what was only an abuse through excess. Moderate use of alcohol is not immoral. Millions of moderate drinkers were denied the right to drink in an effort to stop excessive drinking.
The recognition of sex as being restricted to chaste marriage, on the other hand, has been the societal norm throughout history and in nearly every culture. Nor does it forbid the proper use of sex with a total prohibition as Prohibition did with alcohol. It just channels it into its proper place.
There is no argument that will work, because this issue is not convincing our opponents, it is converting them, and that can only come with presenting the Gospel in the power of God.
When God converts you, you don't need to be convinced; when God does not convert you, you cannot be convinced.
I agree that the ultimate goal is conversion to the Gospel. But that does not mean we should avoid intermediate goals. The limitation of sex within chaste marriage is not unique to Christianity. It was also the norm in most non-Christian societies, thus showing that it can be promoted as a good in itself.
I would disagree: most non-Judeo-Christian cultures provided means for sexual activity outside of marriage, from temple prostitutes to red light districts to allowing for a mistress to homosex as a bond-forger (intercrurial sex with mentors in Athens, sex with fellow fighters in Sparta). The universal prohibition was not against sex outside of marriage, but sex with someone who was married to someone else.
What cultures have never had throughout history is a definition of marriage other than one man and one woman, except in some cases for the rich and powerful who could be polygamous. It was only in Judaism and Christianity that the idea of sex having to be kept within marriage took hold, and that was the prevailing belief in Euro-American society until the removal of Judeo-Christian thinking from society.
I believe what is being asserted here is that evangelism/awakening/repentance (a GOTV for the Lord, if we can put it that way) is needed since the “salt itself has become unsalty.”
I’m not hearing very cheerful things today about how the church body handles divorce, let alone other marital issues. If it is just like the world, it has become a sad farce before the Lord. And attempts to counsel the world on what to do look like the hypocrisy they are. They needn’t BE hypocrisy, but the church has its own homes to purify.