Better to eat the grapes. Then you get Antioxidents and no undesirable fermented byproducts.
The best for of moderation is abstinence and there's plenty of ways to get antioxidents so even if it ws proven that fermentation increased Antioxident levels, that wouldn't make Wine more beneficial than plant based juices and Wine is still more caloric anyway. 3 calories per gram more caloric than normal Carbs, hence why Alcoholic drinks can be very fattening.
Plus there may be scietific evidence to suggest that Alcohol processing in the Liver, prevents normal important Liver processes from being undertaken, until the processing had ceased, certainly it would be logical to assume, that the Liver would have to reduce it's ability to do those things, for a while, assuming it was not capable of adding the processing of Alcohol into the mix, with no let up regarding other processes.
The body can make its own Alcohol anyway, as a byproduct of Glycogen breakdown, without sufficient Oxygen present, (Anaerobic respiration), the same circumstances that permit Lactic Acid production too.
I've often wondered if Alcohol studies are just to curry favour with drinkers, because Alcohol is very taxable and popular, so engineering a balance somewhere between abstinence and binging, would make good economic sense, plus it would give Doctors some moral highground, if someone they had recently told to stop or cut drinking for health reasons, caught them enjoying a crafty whiskey afer hours
Nothing worse for Doctors, than being lectured about drinking by alchies they had to treat, with the possible exception of being lectured about an occasional Cigar, by Cancer sufferers