It's using existing gestures and having them carry out different functions that is unique to the app.
It's like keyboard shortcuts - every program's usage will be different minus a few key ones. Or video games, some buttons do what you expect but some will depend on what the game's design is. Of course there will be some tour or tutorial - how else are we supposed to learn about them?
Double tapping the Home Button on iPhone < How did we learn about this? Double tap? There's no visual queue on the hardware that we can double tap. Did Apple fail?
I kinda get what the author is trying to say but he also kind of miss the point of walkthroughs and tour completely.