Why can’t users make that decision for themselves? Granted, many people choose to buy Apple devices because they do not desire general computing devices and instead desire appliances.
But giving up that control erodes ownership itself. A device not fully controlled by you is not fully owned by you. You may own a license to use it for a limited time. But people do not buy hardware devices with the expectation of actually only buying a license to use them.
Your reference to "general computing device" here is a concept that a particular market identifies with (you being in that market). Attached to it is some kind of concept of free/open. Apple will tell you their devices are general computing devices. I am currently playing around with lidar sensors in an iPhone 12 pro by writing code and pushing it onto my device. The functionality I can build is pretty arbitrary and I would call it general computing. I would agree with Apple.
All of this is not applicable to other platforms (maybe to consoles but I already commented about them on this thread).
Apple has no obligation to make this process easy or even possible, and if the users still buy their products, they clearly don't care enough about these restrictions.
The only way to prevent them is by abolishing their property and putting them in the public domain.