As much as this addresses the specifics of '915, the Verge commits the classic forest-for-trees error of why PTZ should have been patentable in the first place. HN has shown prior art from the 1980s within the past week.
This article doesn't argue that Pinch-to-zoom should be patentable... This article is talking about the actual patent that was infringed upon, which you noticed in the beginning of your comment. Did HN show prior art that invalidates the patent that details the mechanism for determining the difference between a one finger scroll and a multi-fingure gesture? I must have missed those posts.
I'll try to find it later, but: a video showing a two-handed version of pinch-to-zoom (and navigate) on a fixed, non-mobile display, from the early 1980s. I don't believe it was Pike's "Blit" (a/k/a Jerq) interface, but an earlier article.
And: specific to your question, I don't believe the PA distinguished between one-finger and multi-finger gestures, though I'd have to review it more closely.