The difference is there's no laws around your home decor, but there is a clear legal framework around trade secrets. Apple's allegation is that a vulnerability was exploited to access some of the data as well which, if true, carries potential CFAA criminal charges.

For trade secrets, it only requires "reasonable measures" even just having an NDA is enough, even if the rest of your security is wide open. Just because someone found a loophole or grabbed files before their access was revoked doesn't make it legal (under trade secrets law).

Almost certainly the employees at some point in their tenure at apple signed some duty of confidentiality, or some acceptable use policy, etc. which is grounds enough for illegal misappropriation. "You didn't lock down their access enough" isn't a valid legal defense.