This article is clearly written by someone who doesn't understand how encryption works.
> What happens if I log out of all my proton accounts, travel to the other side of the globe, walk into the first library or internet café I find, and log on to mail.proton.me with my username and password?
The keys are encrypted to your password, that's how you can access your data maintaining E2EE.
> What happens if I log out of all my proton accounts, travel to the other side of the globe, walk into the first library or internet café I find, and log on to mail.proton.me with my username and password?
The keys are encrypted to your password, that's how you can access your data maintaining E2EE.