Removing DRM from content you OWN is hardly hacking.
If you live in Canada it’s 100% legal.
Moved this here since it’s drifting away from the OPs question.
If you look at the agreement that you checked as accepting with Apple to purchase content both audio and video you’ll see where it’s a violation of that agreement to tamper with or circumvent any security technology included with the services. That would include both DRM removal and HDCP bypassing.
As to the legalities of it, I would think that would depend on how the country you live in regulates agreements. In Canada I’m guessing that is one of the top reasons Apple has an “Apple Canada Inc.”
I seriously doubt that Apple would chase down an individual that was breaking that agreement only to play content on their private network and not distribute that modified content but the agreement that has to be accepted in order to use the service seems to give them that right if they choose to pursue it.
I’d add that per the T’s & C’s you don’t actually “own” it. You have just purchased the rights to play it whenever you want.
Unless your country allows for removal of DRM for personal use. Federal law trumps T & C.
In some countries there is a permissive clause for “educational and research use” of software, you don’t have to receive consent of the right holder. For example, to study the mechanism and the security of the software, i.e., reverse engineering, is allowed without the knowledge of, and the consent of, the right holder. DRM, music file, video file, secured PDF, ePub, KFX, etc., are also classified as software.