A Gizmodo writer used a really interesting analogy to help illustrate what’s happening here versus what’s allowed under a specific warrant:
When the cops obtain a warrant to search a person’s home, and they find a safe, nothing in the warrant requires the manufacturer of the safe to help police break in if they can’t figure out the combination.
But here, a judge has ordered just that. And she’s used an antiquated law from over 200 years ago to justify it. That law actually might wind up working in Apple’s favor, since it only applies if the order doesn’t create an excessive burden or harm. Apple could — and, next week, probably will—argue that forcing the company to maim its own technology and security features would be an excessive burden that would do unjust harm on its future business practices.
(I saw earlier that you looked into this a bit more, but I thought I’d post my response just in case anyone else had the same questions you did — which were valid points)