Earlier quoted context omitted.
They dictate the capabilities that their device is offered and how the device is designed. It is up to the consumer to decide if that is worth the price of the device.
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?
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).