The article in question claims that links followed from https facebook do have a referrer header:
>In testing links from Facebook and Twitter over HTTPS the referer is present in most cases.
>In testing links from Facebook and Twitter over HTTPS the referer is present in most cases.
"Clients SHOULD NOT include a Referer header field in a (non-secure) HTTP request if the referring page was transferred with a secure protocol."
However, it's possible that Facebook is passing users through an HTTP gateway.
Give it a try yourself: https://twitter.com/vikrum5000/status/256898972478763008 Note the protocol.