The two things are not mutually exclusive. We can have hardware and software that's open to tinker with but still come ready to use out of the box.

Apple's job doesn't end when you open the box.

Unless you want a rootkit installed when you charge your phone with a public charger, it needs to be locked down. These restrictions are made for security and stability. If the average user doesn't need them, then don't enable them. Simple logic.