I'm not sure I agree with the premises that I own my device, which most people seem to take for granted. After all, in the iPhone case, I'm not allowed to root

I'm not sure I agree with the premises that I own my device, which most people seem to take for granted. After all, in the iPhone case, I'm not allowed to root it, install anything I want on it, etc. Apple already controls it, and already decides what I can do with it. So, if Apple decides that it can't be used to send child pornography, how is it different from 'standard' usage restrictions ? Or is it only the fact that it might trigger a call to law enforcement which is a problem, and without this call, everything would be ok ? In other words, would an iPhone which detects child porn and refuses to do anything ('error : illegal content') with it be ok? Or would this be a violation of privacy?