I know that a lot of people hold this view, but I've never agreed. Coming from a family with rampant with alcoholism, I did some research when they were small, and I found that -- without doubt -- letting kids drink at home is a bad idea. It actually increases their chances of having trouble with alcohol as teens and later in life. A quick google search found me a couple articles to back this up:
http://healthland.time.com/2011/04/...help-teens-drink-more-responsibly-not-really/
https://drugfree.org/newsroom/news-...real-consequences-for-both-parents-and-teens/
http://www.nbcnews.com/id/42807670/...k-under-parents-watch-backfires/#.WZ34MmcYlhY
http://www.madd.org/underage-drinking/why21/
Note that these are not fly-by-night references, and they aren't just opinions: they're well referenced at the end of the articles.
You're right, which is why I qualified my answer with "it certainly could happen ... [but not] just as easily" and "some difference". However, these things are better than no supervision and no safety net, which is what the kids on Natalee's trip seemed to have.
The first three articles only talk about studies looking at Ameircans, in which people drinking at home are breaking the law and in which the culture around alcohol is otherwise very different than it is in places where the age is lower.
The MADD articles has a little is intersting. I don't trust MADD any more than I trust Susan G KOmen, but looking jsut at the first referfence in their bit about Europe frmo your linked article provides some fairlygood insight into how they are twisting things and that the link doesn't really support their conclusion that binge drinking is higher in nations with lower drinking ages overall such as in Europe. Nowhere in that article it states that binge drinking or drinking to intoxication is worse than in America (no reference is veer made to the USA) and there is no link to a reference of where the authors of the MADD article got a number for the US that they are comparing the stated European rates to.
The linked research also points out very low rates in Intoxication in some countries and that the high rates are nearly always in Eastern Euroean countries (where culture and economic troubles are going to play a large role, far beyond just age limits)----basically countries with low drinking ages still range from having youth intoxication rates (meaning being intoxicated at least once before teen years) of 2% all the way up to 22% in Europe (with Nordic coutnries being the lowest end, then western Europe then a big jump in Eastern Europe---which makes it pretty dang clear that just the drinking age limit, which is fairly similar in all of these, is not the major contributing factor.
Binge drinking and problems absolutely happen everywhere. But I, personally, see far fewer among my son's peers here than among my nieces and nephew's peers in the US (all the kids are about the same age). I could well be wrong about whether it is really a better way of going about it (I doubt it is worse, but could just be different), but have not yet seen any large scale, welldone research indicating that, certianly not what is linked above.
All I can find are a handful of smaller studies that actually look at rates of alcoholism, etc and those seem to go either way depending on the study. I'd love to see links to truly good, compartive studies if you have them.
Drunk dirving is far lower in Germany though (I do not attribute that just to the drinking age; I am sure prevelance of public transit and also the penalties are a big palyer in that---just as how the amount of drunk driving dropped near when the 21 age came into affect but there were also HUGE campaigns at the time, mostly via MADD, to explain what it was and how dangerous it was, create a social stigma around it, encourage ticketing, etc --- so it is not just one thing that changed right then, no matter how much MADD now tried to frame it as such).