Before we get going, my personal experience with both operating systems is definitely in line with the findings of the study and its data. On my Galaxy SII, I've probably seen like two, maybe three application crashes in the past few months, while my iPad sees several application crashes per week. Back when I still used my 3GS, the situation was the same. Of course, your personal experience may differ.
The interesting thing here is that Android and iOS handle application crashes differently. On iOS, there's no indication an application crashed; you're just dumped back at the home screen. On Android, you get the force close dialog. There's something to be said for this cleaner approach in iOS, but personally, I like to be notified of a crash, but hey, that's just me. This could mean that most people simply don't realise an application has crashed; "I must've pressed the home button or something".
So, if we were to assume the data reflects reality - why do iOS applications crash more often than Android applications? I think a very big difference is how applications on Android can silently update in the background (if enabled in the Market), whereas iOS applications have to be updated manually. Whenever someone hands me their iPhone, I often see them not updating their applications.
Furthermore, Android developers can update their applications way more easily than iOS developers can. Google is far less strict with its market, meaning developers can push updates instantly, quickly fixing bugs. On iOS, each update has to go through the certification process, meaning developers tend to wait with pushing updates to make sure they include several fixes - less updates, meaning bugs can roam free on iOS devices for longer times. All this shows that there's really no 'right' or 'wrong' way to curate an application store.
Of course, there's countless ifs and buts attached to this data, so don't accept it as some sort of clear and unprotested truth. Still, the points raised are interesting.