That case has the specific, very important, wrinkle that he provided a _destructive_ duress code, he could have continued to refuse to provide the unlock code just fine legally. It's the use of the duress code that is likely going to be getting him in trouble and that falls outside of the existing defined protections about being compelled to unlock safes/computers etc containing possible evidence against yourself.

We'll have to see how that case goes but ultimately the reason he's getting in trouble is only tangentially related to his phone being encrypted. It's more correct to think of it like he smashed the phone to pieces (and imagine this definitively destroys the data for the sake of the metaphor) instead of it being about the encryption itself.

He didn't smash the phone to pieces, he gave LE a hammer and they smashed the phone to pieces. It's entirely LE's own fault this happened -- they shouldn't have been trying to get into that phone, and it's their own fault it went wrong.

Though I would expect courts to consider that he knew LE planned to enter the provided PIN, and that the duress PIN would then result in the phone being wiped, and therefore accuse him of doing the wiping anyway.

But I don't think it's this guy's fault at all. LE is the one who asked him under duress, he easily could've feared for his life, and he did no direct harm. It was self-defense at worst.