They cast a really wide net, looking for as many examples as possible where non-browser applications fail to do SSL validation correctly, but then conclude that this will result in a security compromise without fully examining the implications.
For instance, they point out that many SDKs for Amazon FPS don't validate certificates correctly. But I didn't see them mention that the FPS protocol does its own signature-based authentication and that credentials are never transmitted in the clear: it was essentially designed to operate over an insecure transport to begin with.
Likewise, they point out an "unsafe" construction that an Android application that I wrote (TextSecure) uses. But they don't mention that this is for communication with an MMSC, that this is how it has to be (many don't present CA-signed certificates), and that the point of TextSecure is that an OTR-like secure protocol is layered on top of base transport layer (be it SMS or MMS).
So I think the paper would be a lot stronger if they weren't overstating their position so much.