My gut tells me that they don't want to either set the precedent or let it be known that they can access your data and give/revoke access remotely, because it pokes a hole in their E2E encryption claims and opens the door to demands for backdoor access from governments.
It doesn't "poke a hole" in anything. The only way you get the full E2E encryption Apple talks about is if you enable "Advanced Data Protection", which none of the people in the article did, per the article. Apple could decrypt and return the data because Apple has the keys. Apple is refusing to do so.
