IDK my mom used to talk about the parties my grandma would host for her and her friends with drunk kids passed out on the lawn right around when it was changed from 18 to 21. I'm not sure that image is what people think of with a lower age.
I think the attitude to alcohol is a primary reason we here in the U.S. have a different mentality towards it. Here, with prohibition and still commonly held views on alcohol it's for lack of a better term a sin. Kids would drink regardless of the age simply because it's viewed as taboo not because of some age. Make it 16 and you'd probably have earlier drinking than you do now just because of the taboo nature to it.
Regardless I'm not so sure it's admirable to discuss how low some of the countries are in Europe or lack of an age itself given how much alcohol some countries drink. When you have to have a national campaign about lowering your weekly drinking for health reasons you might have a problem

(ahem check out
Truth About Alcohol documentary regarding the UK)
Well, yes, that business about regarding alcohol as a sin is true in a large part of the US (most notably in the Bible Belt), but there are probably equally as many families and areas where it isn't regarded that way. And yes, a lot of *those* are in Irish-American communities, German-American communities, Italian-American communities, and Franco-American communities -- which, as it happens, are always where I've lived in the US (except for one year in Tulsa, where campaigns to quelch underage drinking were the most ubiquitous, FWIW.) Culturally, majority-Catholic and majority-Lutheran or Epicopalian US communities don't tend to view alcohol itself as a sin at all, and never did. Being an irresponsible drunken eejit, however, is another thing altogether, but I don't want to delve too deeply into religious topics. (I love Jarlath Regan, too, but he *is* a comic playing stereotypes for laughs.)
I'm not suggesting that it's OK to be that cool parent who throws juvenile keggers; I had a friend with a parent like that, too; one who was a pretty far-gone alcoholic as it happens. That's clearly endangering minors, and I'm fine with that being punishable. However, as parents we are supposed to model and teach our kids responsible consumption behaviors, and I think it's more difficult to do that with our underage alcohol service laws as strict as they currently are in much of the US, because by the time they can legally drink in most states, even at home, they are already old enough to be largely out from under our parental authority. I think allowing a parent to buy a teen a glass of wine or beer as part of a family meal in a restaurant should never be an issue, or buying them a beer if they are out at a ball game together, or allowing light consumption for our own teens at home. Knowingly letting your kids, or someone else's, get stinking drunk in your own home or out of it was never a responsible thing, and I can tell you that my Irish immigrant parents would never have done so, nor would any of my aunts and uncles. In fact, they never drank like that, either, not even at weddings or wakes (in our village at home we're a family who are known for being notoriously lightweight -- we have a tendency to get maudlin and start singing early on, LOL). I was taught to know my limit and try to stick to it, in or out of Ireland. (And yes, a few times when away at college I did overindulge, but I was well aware that I was impaired, and knew to stay away from car keys, firearms, sharp objects, and smooth-talking men until the next morning -- when, of course, I regretted the headache *and* the singing!) Binge drinking is definitely bad, but finding out just how bad for the first time at 2am in a public place when you are a young adult with no parent around to help take care of you is also pretty bad. As my mother often told me when I was that age, "A big part of growing up is learning to understand the concept of moderation, and it's my job to help you do that." As it happens, my own kids are not fond of alcohol; the older one abstains completely because he doesn't like the feeling of being buzzed, and the younger one has yet to find a drink that doesn't taste to her like vinegar or lighter fluid. We did/do let them have a drink at home under supervision if they wish, and our liquor supply (kept in an unlocked cabinet) has never been raided.
As for the girl with the vodka in her cereal, that's way beyond the bounds of normal, and even the realm of risky youthful experimentation. It sounds to me like she was a closet alcoholic who just took her habit out into the open when she found herself in a place where it wasn't illegal for her to drink.