It applies to general UI as well. Compare side-by-side scrolling speed of a list you get the same result like in the video. iOS scrolling speed in list like email/contact still gives the lethargic speed. This lethargic speed occurs everywhere not just a particular app like Facebook. The kinetic scrolling on iOS is designed that way i.e. lags compared to Android UI speed.
The link to web page loading time shows Iphone still behind compared to S3 (with Flash plugin disabled)
When loading app, Android is slower than Iphone only when the app is not already in the cache (i.e. first time opening). Open the same app the second time, it is faster than Iphone.
I have said Iphone is "smoother" than Android but actual UI speed is still very lacking. You are deceived by smoothness as fast. Android has made strides in becoming smoother without sacrificing speed. Iphone UI moves in slow-motion compared to Android albeit smoother.
iOS is natural? On my PC/mac when I hold page down to scroll, the screen scrolls really fast like Android. Compared to Iphone where scrolling is lethargic like driving with the brake pedal depressed.