Passwords used to be hard. The easiest solution was the reuse the same password everywhere – and many people did that. Using Facebook as an ID across the web helped keep people safer by simply not having passwords for many services at all. Most people would trust Facebook’s security over a tiny startup you might want to sign up for an account with, anyway.
Times change, and online security is now easier to use and stronger than ever. Password managers are built into some operating systems and browsers as standard, fingerprint and facial recognition is supported by some services, and two-factor authentication is increasingly the norm.
In a world where it’s easy to create a unique password for every site you visit, and secure it even further with two-factor authentication or biometric tech, logging in with a Facebook ID seems risky and archaic. But it had its time, even if we’re now experiencing its downside.