In the original Dutch article (https://decorrespondent.nl/845/Dit-geef-je-allemaal-prijs-al...) the author explained in the comments that they used SSLstrip for facebook and live.com
So, the connection was over HTTP and not HTTPS.
They added a padlock favicon.ico image to give the impression the site was secure
Ah. I wonder how hard would it be to extend protocol to let Facebook, for example, state that they will never go https again, so that browser would scream.