As someone who is not an iDeveloper and has no idea what the UIPopoverController does: couldn't you make a case that Apple is deliberately crippling the competition and, therefore, make a case for abuse of a dominant position?
If it were so it then it wouldn't be about being shocking, expected or logical, but about being against the law.
UIPopoverController is a trivial UI element which allows an app to display a kind of tooltip-style contextual view above the app. It would be hard to argue that the exclusion of this API would constitute "crippling" anything, given the number of alternatives which are available.
Apple has no dominant position in smartphones, so you may at best argue they have a dominant position specifically in their own iPhones.... But if Apple making design decisions for their iPhone product line constitutes an "abuse of dominant position" where do we draw the line exactly?
- Should Apple be forced to open all internal APIs to third party developers?
- Should Apple be offering iPhones with alternative operating systems?
- Should there be an open standard so people can build compatible iPhone clones?
No. iPhone is Apple's product, and they decide how far they will go in opening up their platform.
Third party developers are not fully trusted to do the right thing, and as you can see with Android's malware situation, it's a good thing Apple is not letting random developers do whatever they want.
Since Apple is held responsible by both developers and users to have a reliable product, when they decide to make an API public this is a huge commitment.
Apple has to guarantee said API will be supported in a reasonable way in future OS releases, it has to guarantee to users that calling said API won't result in poor UX or security vulnerabilities.
The situation is much different for Apple's own apps, as Apple can then make the personal guarantee it won't be abusing its own APIs to create poor UX and implement malware.
If it were so it then it wouldn't be about being shocking, expected or logical, but about being against the law.