It's not the gestures they are trying to patent but the technology required to transfer those gestures into UI controls, so everyone please stop being Mr Crazy for 5 minutes and understand what is actually being said.
Incidentally, in a few generations time the tablet will also be controlled by none physical input, eventually the technology will be miniaturised further and the Kinect system will find its way onto laptops and tablets, hold it up in front of you and control it like it the same way.
No one has gone Mr Crazy about the Kinect, because you understand the technology and Microsoft still own the patents. This is a clear case of too many people jumping on the bandwagon of hating on the patent system and not enough people understanding what they are patenting or how the patent system works.