But you likely feel somewhat comfortable with them if you purchased an iPhone.
Purchasing an iPhone self-selects people who are comfortable with the idea of the features it is marketed as having, such as being able to take, store and manipulate photos out of the box.
This is also an issue primarily because there is no third-party photo picker extension point. A third party only gets photo picker support if they store their photos into the Photos library. If third party photo apps could have similar integration points based on them maintaining their own first-party library, they would not need to ask permission to manipulate another program's data store.
Also, I don’t actually know Apple’s developers and their goals.