Apple released a whitepaper [PDF] about the safety of the App Store, and the company’s head of user privacy, Erik Neuenschwander, spoke to Fast Company about it.
Without iOS, users wouldn’t have a mobile operating system platform they could choose from that is impossible to be targeted by malicious sideloading. In Apple’s view, in other words: Do you want the best privacy and security possible? Your choice is iOS. Do you want sideloading? Your choice is Android.
First, “if you want X move to Android” is a bad argument. I like Cory Doctorow’s text on the subject. Second, it’s not “sideloading” it’s downloading your software from the internet like desktop users have enjoyed for decades. Apple has smart people and I’m sure they can figure out a way to bring Gatekeeper to iOS.