Wine isn't just food- it has an intoxicating effect and addictive properties. Don't be obtuse, it's not as if adolescent alcoholism is unknown. To take alcohol is an adult decision, not a child's, and to make it "no big deal" is handing the decision to a child. No way.
As for explaining my values, you only assume I don't. Of course I do. I also explain the consequences of acting against our (my wife and my) wishes. And I don't simply say "no". I back up everything I say, so my actions accumulated over years put the force behind my words.
Will my children experiment with alcohol? Maybe, maybe not. Same with sex. However, I can control to a vast extent their ability to have access to both. I also choose to exercise that ability, because it is my responsibility to do so, not society's, and not my kids'.
I deal with parents with your mindset every day... and the kids are in charge of the house. The parents just throw their hands up and say, "What're you gonna do?", as if it's impossible to stop kids from doing anything they've made up their minds to do. That's wrong, and it's a social sickness here in America.
So, do you have kids? If so, are you raising them?