Because Oleophobic coatings on glass is a completely different idea?
I have used phones before with oleophobic claims and the bottom line is they do not prevent fingerprints on screens. The reality is that fingerprints are only an issue when the screen is off because it makes the glass look dirty, but when the screen is on, and unless you have been inhaling Cheetos for a few hours while using your tablet or phone, you are never going to notice fingerprints.
If Apple is patenting how to apply this coating on sapphire then they have a claim, but to claim the "novel" idea of simply using this coating on another type of display surface I do not think will be granted.
Oleophobic is just a marketing gimmick that tries to make people believe that a device with it is better then a device without it, just like sapphire. Apple is the king of patenting marketing myths.