A phone is just a computer. Why should they not be allowed to sell a computer that is locked down? There are lots of other computers for sale, some of which are locked down some of which are not. There’s nothing inherently or obviously anti-competitive about selling a computer that has lots of guardrails, and, in fact, that’s how they have distinguished their product from others.
Locking down a system is also the way to prevent people from installing rootkits, fraudulent banking apps, bypassing the CSAM filter or defeating DRM. I think it's delusional to expect governments to blanket ban locking down computers. Most governments would likely try to gain that kind of power themselves.
Counterpoint: Users should have the right to the same level of control over code execution as the manufacturer after the sale. Does Apple have the technical ability to control all iDevices? Yes. They have the private keys used to sign the OS and firmware for all their parts. Therefore users should have that same degree of control over everything, including TZ/Secure Enclave.
This shouldn't just apply to Apple or even phones in general. It has to be a universal regulation for all devices sold on the market for any purpose. If it runs code, it should be subject to that rule.
Apple (or anyone else) should not be allowed to violate / subsume consumer rights for its own business interests. Consumers should have access to the system literature of a device and be able to unlock the bootloaders and install any other OSes on it.