Subpoenas can be issued by any law enforcement agency and carry little if any legal authority. Generally, a subpoena should be tossed in the trash, considering the legal "weight" it carries. So if they are responding to subpoenas or "requests issued by a government agency", as they admit they are, then they are going beyond what is required by law and unnecessarily disclosing information.
There is no such admission. You should read what Apple have actually said, not the white space between the words...
Like many companies, Apple receives requests from law enforcement agencies to provide customer information. As we have explained, any government agency demanding customer content from Apple must get a court order. When we receive such a demand, our legal team carefully reviews the order. If there is any question about the legitimacy or scope of the court order, we challenge it. Only when we are satisfied that the court order is valid and appropriate do we deliver the narrowest possible set of information responsive to the request.
Total Number of Law Enforcement Account Requests Received
The total number of account-based requests issued by a government agency and/or a court that are received by Apple and seek customer data related to specific Apple IDs, email addresses, telephone numbers, credit card numbers, or other personal identifiers. Account-based law enforcement requests come in various forms such as subpoenas, court orders, and warrants.
Number of Account Requests Where Apple Objected
The number of law enforcement requests that resulted in Apple refusing to provide some data based on various grounds, such as jurisdiction, improper process, insufficient process, invalid process, or where the scope of the request was excessively broad. For example, Apple may object to a law enforcement request as invalid if it was not signed.