Not odd at all imo. I have mixed feelings on this issue. When my Mom was growing up in Italy there was no drinking age. The attitude there is totally different. My Nonna would send her out to buy a bottle of wine (at age 8 or so), and on the way home my Mom would take a few sips because she liked the taste. When she was a teen here in the U.S. one of her uncles wanted her to taste beer or something so she wouldn't be curious and get herself into trouble elsewhere.
I don't know if no age limit would work in the U.S. I agree with other posters who say it is about attitude.
From a psychological perspective, what is forbidden becomes more attractive, at least for teens. I don't have any answers as to what the right way is for the U.S.
I don’t know about the forbidden fruit angle.
It seems to me one of a double standard. Many children see adults behave in absurd ways - drinking, sexuality, cursing - and, yet despite their good behavior they are treated like children. Adult no longer means mature, but over 21. Why not call a spade a spade?
Maturity is a behavior not an age.