He's mocking the triviality of the patent. Patents are supposed to protect an innovative new process or technology. Putting a button on a screen to activate a previously existing technology is just spending money to try and cripple competitors who accidentally infringe.

Trivial, I agree.

But I don't know what is sadder: Apple patenting this, or the fact that very few (if any) phones did it before the iPhone...

Many many phones did this sort of thing before Apple. What they have patented is to display a button for it.

The idea of patenting it has roughly the same amount of hilarity.