When reading patents, only the claims matter. In this case, anything that matches claim 19, which is anything that does bounce-back scrolling the way iOS does it, is infringing.
I've just read claim 19 about 5 times. I also studied Figure 5, which seems to lay out the process in a way that's a little easier to understand.
I have absolutely no idea how what is described in claim 19 is not the "idea" of inertial/bounce-back scrolling.
As far as I can understand, the layperson's explanation of claim 19 goes something like this: drag some content on a touchscreen at the speed that the dragging finger is moving, once you hit the end of the scrollable range, start slowing down the speed at which the item moves, and show a different background to make it clear you've reached the end of the list, once the finger releases move the list back into place.
I'm trying sentence by sentence to translate the words in the patent claim to english that I can understand. And it sounds to me like this is the general idea of this method of scrolling. There are no specifics, no specific easing algorithms, no specific method of tracking the finger's movement, no method of actually implementing this at all.