There is no valid reason not to disclose that information to the user inside the rejection letter. It's not as much a failure of Apple's legal department as it

There is no valid reason not to disclose that information to the user inside the rejection letter. It's not as much a failure of Apple's legal department as it's a failure of the legal system where this is a-ok. Doesn't matter what the app is - maybe user tried to publish an illegal app, but that should be clearly communicated. It's the civilized way.