A Strange Halakhic (sort of) Thought

[debka_notion]

So there's a general principle in halakha (Jewish law) that the law of the land is the law. (Dina d'malchuta dina, I think- I don't know Aramaic, so this is just what I remember a teacher telling me it was in high school. It was Rabbi Eli I think.) So, why do the orthodox/observant (pick the word of your choice) folks drink underage? If they're so stringent about other aspects of the law, why break one that's pretty easy to follow? SOmehow I'd think this would be a more common idea.

Note, this is not intended to be a criticism of anyone in particular- just a thought.