[snarfy]

It's all pretty terrible. For problem (1) why does the language allow it? And why are they doing it this way? Did Apple not provide an official way?

[cosmic_cheese]

With Objective-C's nature as a dynamic language, there's no way to make APIs fully private and unusable to third parties. Despite heavily embracing Swift in recent years, much of AppKit and UIKit are still written in Objective-C.