I thought the idea of things in moderation was common knowledge by now.
In balance, drinking sugary soda is worse for a diabetic than a moderate amount of EtOH, in wine or spirits. Soda has more sugar grams per serving. A can sends blood sugar sky-rocketing. It's a full meal of empty calories. Alcohol has a blend of effects and also is beneficial in moderate quantities. At least switch to diet soda if you are trying to quit.
I think it depends on how much of either you drink. A little red wine is good for your heart. However, there are a lot of things in soda that are bad for you BESIDES the sugar that people are ignorant of. Soda is really really not good for you in any case whatsoever.Unless you have made your own homemade soda out of wholesome ingredients. And especially diet soda. It is really bad for you. Most alcohols are bad for you too, with all of the extra things they add to them. I think probably drinking a good home made red wine in moderation (maybe a glass once every couple of weeks) would be better than drinking soda. In my humble opinion ;)