Facebook accepts "Baggins" as a last name and even doesn't allow some real names (unless they verify their names iirc). 
Once enough people report you (for anything, not just having a fake name), then you will be asked to provide Facebook your ID. It has happened to me countless times. It is a Facebook policy that you use your real legal name. https://www.facebook.com/help/112146705538576
If you're having trouble entering a name, change your country, language to one that uses that name and then change it back afterwards. That works most of the time.
I don't see why Facebook is not a good comparison in this respect. Facebook may take action against buying/selling, proposing that bitcointalk can consider the same.
Well for one, all of this is in vain as FB accounts are still farmed/bought/sold. And the other is facebook is a RL social media as you call it, very different situation to bitcointalk where a lot of people are anonymous and an identity could change hands without many noticing. People would notice if you sold your FB account right?