Are they unrelated?

The article is about a tradeoff between security and user experience, claiming that a given practice is bad experience without any security gain.

The Ashley Madison leak shows that there are plenty of vulnerable users who are not educated to even "the most basic" things to do to protect their privacy.

It's also a question of user experience to protect users against themselves, or against threats they don't know about.

Saying "it's up to the user to do the right thing" isn't really helpful in the context of discussing account creation/login UIs.