The article says: "As for encryption on the Pinephone, the only OS that currently makes it easy to enable is PostmarketOS". And this is false, as there is also an easy-to-use installer for Arch Linux ARM with full disk encryption: https://github.com/dreemurrs-embedded/archarm-mobile-fde-ins...
While I grant this is easier than some of the other options (e.g. encrypting data folder in Ubuntu Touch), I don't think this fit what I meant by "easy" (which included graphical steps, and didn't require anything separate from the phone itself during installation).
Nonetheless, I do appreciate the community forming around this. For a long time in 2020 it felt like encryption was going to be a "when we get to it" task, so it's good to see more things popping up.
Disclaimer: FWIW the closest I ever got to Arch proper was Manjaro, so I definitely didn't do an exhaustive search of every distro.
I know at least Mobian uses a version of the pmOS installer (and that is what I think the Librem 5 will be using for their installer too). But Mobian does have FDE from a graphical installer as an option.