but I also think from an ethical standpoint that it's super messed up that Apple won't voluntarily comply.
Nope: if the data exists, it is only a matter of time until a government decides to abuse its power to way more of it than it has legitimate uses for or for it to leak either by accident, sabotage or hacking. If you don't want the potential liabilities for negligence or any other applicable crime, your best option is to not have the data in the first place. If I had to design an SE-like system, I'd make the main key internally generated every time the device gets factory-reset so even the manufacturer has no clue what it might be. The only way to get the keys out would be atomic-force microscopy to directly read the NVRAM cells after polishing the CPU substrate thin enough to read them.This means that the only way anyone is getting through this back door is if both Apple and the FBI both agree that it's appropriate.
If the SE key is only known to the CPU it sits in, then there is no amount of jail time or torture that could coerse Cook into doing anything.In the same way as Chelsea Manning is held without a trial until she agrees to testify, how long will be before Tim Cook lands there "until he cooperates"?