Free radicals are a good thing? I think you are confused. Most carcinogens are thought to act via being or producing free radicals. The free radicals trigger errors in DNA transcription which is thought to result in cancer.
Antioxidants are thought by some to decrease free radical production and giving protection from cancer. Of course, the lab results of heroic consumption of antioxidants are mixed.
Grape juice is very high in calories and high in simple sugars. Those would be bad things. Red wine, at very moderate levels, is thought to have a slight health benefit. I might add that the emphasis here is slight. Alcoholism has a decidedly major adverse health risk. Some people can consume alcohol at low levels and some can't but nearly everyone thinks that they can "handle it".