This seems to be a highly controversial topic with contradictory claims and opinions. I think the best way to go about it is to check blood sugar levels after drinking wine. Each person reacts a little bit differently. So I think that wine may be okay for one person but not okay for another. Diabetics who have a glucose meter at home can check their blood sugar levels one hour and two hours after consuming wine to see the effects. If blood sugar levels are higher than normal, obviously wine is not a good idea.
I did this and I discovered that wine does raise my blood sugar. So I personally avoid it. I have diabetes though. I have no idea what role wine plays in preventing diabetes. But I do believe that diabetes is mostly due to genetics and lifestyle. So I doubt that a single food or drink can prevent it or trigger it.