In filings to a court during the FBI legal fight, Apple addressed this topic head on. The reason it was brought up in the first place was because national security establishment water holders were putting out the idea that Apple makes exceptions for China, and the Department of Justice parroted it [1].
From Apple's filing [2]:
>Finally, the government attempts to disclaim the obvious international implications of its demand, asserting that any pressure to hand over the same software to foreign agents “flows from [Apple’s] decision to do business in foreign countries . . . .” Opp. 26. Contrary to the government’s misleading statistics (Opp. 26), which had to do with lawful process and did not compel the creation of software that undermines the security of its users, Apple has never built a back door of any kind into iOS, or otherwise made data stored on the iPhone or in iCloud more technically accessible to any country’s government. See Dkt. 16-28 [Apple Inc., Privacy, Gov’t Info. Requests]; Federighi Decl. ¶¶ 6–7. The government is wrong in asserting that Apple made “special accommodations” for China (Opp. 26), as Apple uses the same security protocols everywhere in the world and follows the same standards for responding to law enforcement requests. See Federighi Decl. ¶ 5.
and a declaration from Craig Federighi personally [3]:
>Apple uses the same security protocols everywhere in the world.
>Apple has never made user data, whether stored on the iPhone or in iCloud, more technologically accessible to any country's government. We believe any such access is too dangerous to allow. Apple has also not provided any government with its proprietary iOS source code. While governmental agencies in various countries, including the United States, perform regulatory reviews of new iPhone releases, all that Apple provides in those circumstances is an unmodified iPhone device.
>It is my understanding that Apple has never worked with any government agency from any country to create a "backdoor" in any of our products and services.
>I declare under penalty of perjury under the laws of the United States of America that the foregoing is true and correct.
That was a few years ago, but Tim Cook basically reaffirmed that a few weeks ago in this interview with Vice [4]. The new law means Apple's Chinese iCloud data needs to be stored in local data centers, but Apple continues to maintain sole control of the keys. Whether you believe them or not, or whether you think that's a meaningful distinction is up to you. But end-to-end encrypted services like iMessage or iPhones itself, remain so and are still unblocked in China.
You might be wondering why Apple seemingly gets an exception when services like WhatsApp are blocked. The answer should be obvious: Apple being an old-world company that still makes products in meat space, (indirectly) employs a lot of people in China. That gives them leverage that other companies don't have.
So they have to comply with certain Chinese laws such as taking down the NYT app, VPN apps, being unable to operate iTunes Books or Movies in China, etc. But that's a small price if it means their core products remain uncompromised.
[1] https://www.lawfareblog.com/deposing-tim-cook
[2] https://assets.documentcloud.org/documents/2762131/C-D-Cal-1...
[3] https://www.documentcloud.org/documents/2762118-Federighi-De...