Apple has already given them Farook's iCloud backups, just not recent ones since they don't exist. If Alice was murdered, and Bob was circumstantially implicated, but had an iPhone that had some kind of data recorded that placed him at the time and location of the murder, what law exists for Apple to protect Bob's data if that data was uploaded to Apple for backup purposes?
Sure, it would be nice for Apple to oppose even "valid" warrants for iCloud data backups, because I trust them to keep my data safe on my device, so why should I have a reduced expectation of privacy when using their services. After all, they have billions in cash in some Scrooge McDuck mansion just waiting to be spent on lawyer fees, right? /s
I agree that the second case - court order to create new software - is a lot more obvious and clear, and deserves opposition in court.
The reason I'm being so pedantic is that it's important to disagree with the notion that corporations should roll over in any situation that involves claims of terrorism. Lots of people think that, but it throws away an important part of our legal system.
I'm not saying they're wrong to obey court orders.
I'm saying that people will be saying that Apple fight against court orders when in fact they don't usually fight the court orders. They normally give out the information.
When warrants are clearly legal, there is nothing they can do to fight them.
They only give out the information they are legally forced to do, and are doing everything in their legal and technical power to reduce that as much as possible.
The idea that the Govt can only issue "valid" warrants is flawed. The Government is just people, and like everyday citizens like myself, we're perfectly capable of breaking laws, either unintentionally (eg, giving a lift to a friend who has undisclosed controlled substances on their person (state dependent)) or intentionally (eg, murder).