Because it's an odd association, and I'm not even sure if there's a chocolate island in the version I played (quite sure there isn't, actually)...
Tom Well, to me it wouldn't make much sense to associate 'Chocolate Island' with anything other than Mario Kart.
The Netherlands Oh, lol, well, then I guess I didn't play the version with a chocolate island in it - I've only played a pretty old version (7?).
Wait, what? That's the second newest, I believe it's from 2011. Chocolate Island's from 1991, which is a slight bit older.