Well I disagree apple makes the hardware and can do what ever they want. They make money off you using iOS itself and they are very happy with it so why should you be able to install a different os.
I brought the hardware, so hardware belongs to me. Now, the software is licensed to me, so Apple can do whatever the hell they want to their OS and if I agree to the term and condition, I have no choice but accept.
Hardware is other story. I own the hardware, i have right to do whatever they want. If I wish run Android on my hardware, I should able to.