You need to consider the cost of preventing bad devices and bad UI extensions. The cost is just what you see in iOS: Limited choice of devices. Restrictive censorship rules for users and developers. No checks and balances.
Restrictive censorship rules for users and developers.
If the government isn't doing it, it ain't censorship. Look at what quality filtering through an approval process did for the video game industry. The same force is in effect on iOS, and the quality of iOS apps is consistently pretty high, especially when compared to Android.
Scrolling was total ass on my Epic 4G until I loaded some custom ROM where they did some sort of low-level magic to deliver an "ICS-like" experience on a Gingerbread code base.
It still sucks, though, because unless you have a GNex, to get this UX on Android you have to visit some forum where l33t kids hang out and dink about with your phone, flashing its ROMs and potentially bricking it, and only then can you have something that vaguely suggests an iPhone in smoothness.
With Apple, it comes with a butter-smooth UX right out of the box.
If the government isn't doing it, it ain't censorship
It is tantamount to censorship once you have chosen iOS, because that choice makes Apple the government of your content.
But whatever you choose to call it, fact is that they restrict content based on value judgements that go well beyond anything you could ever call "quality assurance". They ban everything controversial regardless of quality.
You need to consider the cost of preventing bad devices and bad UI extensions. The cost is just what you see in iOS: Limited choice of devices. Restrictive censorship rules for users and developers. No checks and balances.
Scolling works well on my Nexus S by the way.