You are correct and I don't get OP's point. Don't want apple rules, don't use apple products. They are the business, they can do what they want with it, right?
We have consistently made exceptions to this rule in situations with limited choices. We would not abide by the electric company dictating a range of things, even of you have the option to run your own generator.
The truth is there are two reasonable platforms, as long as that is the case we should apply scrutiny.
Car makers cannot do anything they want and call it a car. The motivation there is safety, but it's long been argued that personal computing devices are today extension of our lives.
Even more comparable is postal rules: at least here, there are very explicit rules about opening someone else's mail, or even destroying it. Even if postal/courier services are businesses, they have to operate within the boundaries a society sets up for them.
And finally, you can take it even further: some "businesses" operate on the fringes of legality and sometimes illegally too (think loan shark operations, casinos, betting markets... but also "protection services" and similar).