Let me give you an example that may help you understand the debate here over alcoholic wine verses non-alcoholic wine.
As Christians, we all are in agreement on many things such as Jesus is Lord God, The Son of God, A person of the Trinity, He is the attonement for our sins. But on many issues we do not all agree, such as OSAS, TULIP, sin nature, music, baptism, etc. On issues such as these we have debate boards just for Christians who agree on the essentials of Jesus Christ, but like to debate such non-essentials that do not determine if one is a Christian or not.
We cannot deny that there is a divide among Christians as to whether or not wine is always alcoholic when spoken of in scripture or whether the scripture speaks of both alcoholic and non-alcoholic wines.
I have heard both sides of this argument and each side has some good points to share. Such as the one you bring up about preservation of the wine or juice if you will. I gather your point is that the alcohol works as a preservative. I don't know, does it? I know they put the juice into wine skins. Could it be that the juice stays preserved because no air can get to it? again, I don't know. But maybe you have a point.
So back and forth we go about the wine. Was it alcohol, was it not. Back and forth, back and forth. However, what we do know for certain and we should all have absolutely no disagreements about is this; Jesus Christ is King and High Priest. Jesus Christ has made us kings and priest (Rev1:6). So when the scripture reads that kings are not to drink wine nor strong drink (Pro 31) then we ought to obey and let the wine for the unbelievers. Do as Jesus did and declare that you will no longer drink any wine until Jesus comes back when He says He will drink it a new - whatever He means by that we will find out then.