From another take on the same story:
"Crappy developers will make crappy apps regardless of how many layers there are, and it doesn’t make sense to limit source-to-source conversion tools like Unity3D and others,"
It doesn't make sense unless you want to inhibit developers from making their apps available across a variety of platforms.
Android really seems to be worrying Apple, it's doing quite well wrt sales and is clearly a challenger. Trying to put some sort of barrier between platforms is probably the only tactic Apple understands, having learnt that from Microsoft.