The grapes used to make the juice you buy at the store are not the same grapes that are used to make actual wine. The person who wrote that recipe doesn’t know what wine should taste like, and I wouldn’t trust that recipe.
The grape juice you buy for drinking is mainly made from Concord grapes, which won’t make something that tastes in any way like real wine. You need grapes like Cabernet or Pinot Noir (for example). These aren’t just the names of wines, they’re the names of the varieties of grapes used.