According to this
news article, FB is allowing dogecoin, digibytes, einsteinium, fedoracoin, mintcoin, reddcoin, quark, worldcoin, vertcoin, karmacoin, earthcoin, trollcoin, HTMLcoin and donationcoin. I wonder Bitcoin is not in the list !!! Does it mean that Facebook board of directors understood they are a bit late in Bitcoin mining and hence mined other alts and now boosting those through their platform for quick profit ?
p.s. Juck wont probably like Bitcoin as Winklevoss hold 1% of it.
there are two possibilities, the first one as you say, fb has been left behind on the way bitcoin and they chose to follow the latest being the moment and think it will all be as good as bitcoin later. second chances, they just have not been published, are preparing well for bitcoin.