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?
That is right. I agree with everything. I don't say bitcointalk.org should do that and allow people to use only their legal names lol.
Just suggesting if FB is doing something to prevent it, bitcointalk can too. Granted it won't be 100% effective. But it gives a better impression on the forum.
Two years ago, I was genuinely surprised when I found that account sales aren't officially restricted. To anyone new, it could give a message that it is accepted in the community[1].
Similarly, there could be additional measures like allowing users to be reported (if there is sufficient reason to believe that the account is purchased/sold, or the owner has undergone a rather sudden change of personality) and even displaying 'the password has been changed recently warning' in a more visible place.
[1] I agree that not restricting does not mean encouraging, but the difference is when you expect something to be restricted and when you realize it is not being restricted and there are no rules against the same, it gives the impression of being a completely ordinary and 'okay to do' activity.
Right now, if an activity farmer gets away with it, the sale is almost guaranteed.
Disclaimer: I don't have first hand experience in trading accounts. This is just what I think and my opinion. As an ex-campaign manager, I have a reasonable idea on how buying/selling accounts affect spam.
Trading accounts is discouraged. I think we could go one more step.