It actually makes sense for them to defend the developers: after all, would you work in an ecosystem where you can get sued at any time without being protected by said ecosystem's owner?
That's a little to generic. You can still be sued for infringing on a patent in your software and Apple won't care at all. The reason Apple cares here is that developers are being sued for using Apple's APIs and developers have no choice but to use those.
If Apple doesn't succeed in the courtroom, I can't imagine them having any choice but to lay down a significant amount of money to either get a license that covers the app developers or to buy Lodsys outright.
