They are licensed for use on a mac, not for distribution to a client machine be it an iphone, Blackberry or Android.
Please give us a link to the license specific to those images from that API, and point out where it states they are licensed only for use on a Mac. You can't because there isn't one. It's a grey area, however what RA were doing is not unexpected, and indeed, it's exactly what the remote app does from Apple.
Quite apart from that, it's pointless to argue over trivial licensing issues. Apple can probably get away with this in a strict legal sense; I'm sure they have some get-out clause saying they can reject any app they please for any reason. No one needs to play the apologist for Apple - if they want to play hardball, they will, and the only thing developers and users can do about it is publicise their complaint and move to other platforms.
The argument is not over whether they *can* do this and get away with it, it's whether they should. If they continue to make life incredibly difficult for developers, large potential partners will start to look elsewhere, and with them the users will follow. They've already lost Google due to their foolish intransigence, and will see less innovation in their maps app as a result.