Anyone know the official reason?
When XBMC was originally developed for iOS, it was done using APIs that Apple doesn't allow developers to use.
That means that if it was submitted in its current form, it'd be automatically rejected by Apple.
By not working within the App Store ecosystem, the developers aren't as restricted in what they can do.
As an open-source project, development is driven by the community, and it seems that they're content with just making it available on jailbroken devices. Making it suitable for submission to the App Store would take additional work and could mean that they'd have to drop features.
Maybe apple would be a better recipient for your question as anything any one here says will be pure scatologic information.
What makes you say that?
My post was pure fact.
The XBMC developers have clearly stated that they make heavy use of non-public APIs, and any "idiot in a hurry" knows that the App Store Guidelines state:
Apps that use non-public APIs will be rejected