Revoking access isn't a secret channel nor harassment.
> Your rights under this license to use and access the Content will terminate automatically without notice from Apple if you fail to comply with any of these provisions.
And cutting off access is quite possibly reasonable. But they've gone quite a bit farther than "no notice" in refusing to answer any questions after the fact (or even point to the contract and any provisions they may think he is in violation of, if this is not just wild speculation) when approached by him. It makes their position that this is some sort of contract dispute far weaker. I assume there is an arbitrage clause in the contract? Has Apple contacted that party yet?
If he has a case, then he can invoke the arbitrage clause.
Given that there is clear public evidence that he is misrepresenting what happened and that he has profited from breaking the NDA, why is any of this work that Apple should do?
> Your rights under this license to use and access the Content will terminate automatically without notice from Apple if you fail to comply with any of these provisions.