Well, what's sauce for the goose is sauce for the gander. Apple has spent years building a tightly controlled walled garden and blocking any way for users to choose for themselves what software to run on their device. Only very recently (in the EU) have regulators started to push for greater openness. But of course, if Apple creates a locked-down device with total control, authoritarian governments will want to take that control for themselves -- and Apple, "obeying local laws" has no way to refuse those demands.
If your iPhone allowed you to download and install your own software, and not just as some special concession in certain markets but as the normal way it works, then it would be much harder for China or other countries to block particular apps.
And yes, there are certainly arguments in favour of a walled garden, for banking apps or for movie playback with DRM or for corporate paranoia about employee devices. And arguments against it too. It's not my intention to open a big discussion on those right now, just to note that Apple is getting a taste of its own medicine.