No, the others had it right. To draw on the analogy some more, the US isn't invading Europe to open the safe deposit box: it's ordering Microsoft to produce documents that it knows they possess, which is something that courts all over the world are allowed to do and do all the time. As a US company, Microsoft is subject to US law, even when abroad (e.g. laws outlawing bribes in foreign countries), including orders to produce the requested information. If I'm the bookkeeper for an organization, the courts can order me to produce the books, regardless of where I'm keeping them. Doesn't matter if they're in a safe, the Caymans, or outer space, I'm still expected to produce them...or provide a very good explanation for why I can't.
And that's the important wrinkle here: producing the documents would force Microsoft to violate laws in the countries where the documents are actually located. For all the US courts knew, maybe Microsoft had a server farm in Redmond where the files were located, so it's possible that Microsoft could have produced the documents without violating any laws. Now that they've made it clear that isn't the case, however, it's time for the courts to decide which way things should go.
Even so, I think it's pretty obvious that the US knew full-well what it was doing and that they're not acting in good faith nor anyone's best interests. As an American, the last thing I want to see is that data getting handed over.