I know that minors can't be sold liquor and other alcoholic drinks, but what about cooking wine? It's not to drink and the alcohol dehydrates when it's boiling.
No, cooking wine still has alcohol in it and if you're a minor you can't purchase it. Although most people will use it for cooking, stores can't be 100% sure what you are doing with it so they have to be safe and only sell it to 21 year olds and older.
Cooking wine is not drinkable. Have you ever tried it? Its way too salty to consume by itself. This is why minors can buy it. They put salt in it so that winos won't buy it. Rubbing alcohol is similar. They put something in it to make you throwup if you drink it. A lot of people were buying it for drinking purposes.