N.B. The above irate comment is from me. I finally found the old email and got my registration email address, and discovered the reason for the confusion: the procedures for logging into an existing account and creating a new account are virtually identical. This is some of the most dysfunctional UX design I’ve ever run across. “We’ll mail you a login link”? Not all my devices check all my email accounts. What if I’m on a device that doesnt have access to the email account I registered with? I can understand confirming the email address on registration, but insisting on reconfirmation every single time the user wants to log into the site? Has the fact that no other site on the internet uses this UX pattern not clued you in that it’s terrible?
Password authentication. 2-Factor, with an authenticator app or SMS factor, if you’re really paranoid that hackers are just DYING to get into people’s Medium accounts and maliciously post bogus opinion pieces in their names. But “we’ll mail you a login link”? I feel like that should be followed by a Terry Gilliam cartoon of a giant foot coming down, or something. It’s ludicrous.