The iPhone OS 3.2 SDK (which is used to build iPad apps) provides explicit developer support for detecting the pinch gesture, in the form of UIPinchGestureRecognizer:

http://developer.apple.com/iphone/library/documentation/UIKi...

http://developer.apple.com/iphone/library/documentation/Gene...

We don't know the whole story here, but those saying that this rejection happened because Apple only wants its own apps to use the pinch gesture clearly have no clue what they're talking about.