In this discussion, maybe we need to separate legal obligations from moral ones.
Does Apple have a moral obligation to help the FBI?
What I would like everyone who answers "yes" to that question to consider is:
Do you honestly think the FBI will find evidence on the phone that is worth the risk it poses to the security of everyone else's data?
Ask yourself, do we already know why these people did what they did in San Bernadino? I think the answer to that is a solid "yes".
Do we think we may find another second-tier sympathizer who aided them (like the guy who purchased their guns for them)? I think the answer to that is "possibly".
Do you think we will find evidence of a larger domestic terrorist network and exposing said group will prevent future attacks? I think the answer to this is "not at all likely" given what we already know about the killers.
The FBI is only saying they want into the phone so we can "get all the answers" etc. I'm telling you, if Apple hacks this phone, we're going to find it's as empty as the killer's souls were the day they committed these acts of terror. Or porn. We might find some porn.