I'm not sure why i've got dragged into this. I don't farm merits, and I don't sell or exchange them.
I think he has a problem with you guys that keeps on getting more attention to the public, and maybe it's the reason for you to be dragged on this situation though.
As I've been looking around on this BTCforJoe challenge, I can't see any problem and can't really tell that this is just for merit farming. As for nullius is also one of the participants of this said challenge and considered as a quality poster.
And IMO, He's just jealous of you JOE.