It seems like some people think that Apple should have sold a hackable device. But they didn’t — they made it clear the iPhone was restricted to one network, the same way many other cell phones manufacturers do.
Their EULA clearly states this– it’s not a hacker playground: don’t modify it. That’s not “controlling” — it’s simply a common way to sell a product to ensure a consistent user experience.
No one needs to buy their product if they don’t agree with that restriction.
So if you break your user agreement and hack an iPhone and then encounter problems later as a result of your actions, whose fault is that?