Unhelpful
Maybe Apple are trying to avoid doing this as a marketing device. They want to put the message out that "We care about your privacy, iPhones are secure" and they care more abou their brand than they do about helping the FBI. If that's the case then they're just your standard amoral corporate bastards, nothing new.
The other possibility, that they feel they are taking a moral position is stranger to me. There has been a lot of discussion of surveilence and encryption and there are good moral reasons to stand up to the government on backdoors and bulk collection. This however is different, it's being done in the open, following due process, ordered by a judge. There was no national security letter gagging Apple from disclosing that they had been asked to do this. There is no suggestion that this is a fishing expedition, it's the phone of a dead terrorist.
If companies refuse to help in this situation, when the state is doing everything right, all they are doing is providing great ammunition to the people who say ban encryption.