Well said.
According to this site, to be eligible for a patent an invention 'must not be obvious to someone with knowledge and experience in the technological field of the invention'.
Before the launch of the iPhone, if you had given 1000 people (people with knowledge of various touch gestures) the task of inventing a method for flipping between photos with a touch interface, how many would have used something like 'previous' and 'next' buttons, and how many would have used a swipe gesture? That would be an interesting experiment if it were possible, but I'd guess a good percentage would arrive at the swipe. It is just so similar to moving a physical photo print off the top of a stack, or even turning the page of a book (which had been mimicked before on the desktop).
I agree. I would actually prefer touching the side of the touch screen to change to the next photo instead of swiping but somebody probably patented that too.