This is sort of going back to what I was saying in my original post though. Encryption isn't a utopic vision of privacy, it is the middle ground. It's not harder today to catch child pornographers than it was before the Internet existed -- it's easier. The fact that we have encryption is being balanced out by the fact that we also have video surveillance, and remote exploits on Internet connected devices, and more payment tracking.
The FBI is not looking for a sensible, middle ground between privacy and bringing people to justice -- the argument they're making is, "if even one criminal escapes, that's too many."
Again, if we were in the opposite situation, if encryption did really mean that we couldn't catch criminals any more, then I'd be more inclined to say this was a complex problem. But the 'going dark' problem is largely a myth; with the advent of the Internet, it has never been easier to monitor citizens or access their data.
This is only a difficult question if it is genuinely a question between anarchy and encryption, but we're not even close to that being the choice we have to make.
You may not be of the opinion that every warrant should be executable no matter what, but when the question is put into the context of modern surveillance, it seems obvious to me that this is the FBI's stance.
This is always the example used to justify anything unreasonable to suspects. For me it's an automatic argument loser, like Godwin's Law.
(If I have a DRM encrypted file that I don't have the keys for, am I now committing two offences? Are law enforcement entitled to a free copy of the HDCP keys?)
Mob mentality doesn't make a very good government, especially when manipulation of information comes so easily. No matter the crime, we can't start the basis of infringing upon an individual's rights on "well most of us on the island agree we should do this". William Golding illustrates this well in Lord of the Flies.
The canonical example here is child pornography. Consumption and distribution is a crime. If a person destroys it before the state sees it, well, that may be destruction of evidence, but the state will never know. If the person can have full access and go back to consumption and distribution, then justice can't be done, and most people agree it should.
I don't think that any warrant should be executable. I'm saying this problem is complex, people are coming up to ways to address it, and they're not the utopic visions of personal privacy-- they involve unconvicted detention, coercion, etc. Miscarriages of justice.