The point is whether Apple's ideas are worth granting a monopoly over.
I recall playing with a Microsoft Surface the year before the iPhone got released, and lots of the mechanics were very similar. Pinch-and-zoom is the 'one-click-shopping', or the 'press tab to move to next selectable UI element' (also patented) of the touch interface; if you're being paid to develop it, you'd think about that concept in about five minutes.
Furthermore, do you really want to live in a world where Apple gets a monopoly on touch gestures? Describe a different zoom-in mechanic using only two fingers.