Or maybe he's just trying to do anything he can to get under Conor's skin and make the fight happen. Floyd is clearly interested in it and isn't just talking for the sake of talking, he does want it to happen. Not in MMA of course, but boxing, which is something Conor said he's definitely open to.
The issue isn't Conor not taking the fight, it's the fact he's under contract and Dana/UFC doesn't want to co-promote just like what happened with Randy/Fedor. Dana/UFC have no interest in co-promoting anything, especially if it's with M1 Global.
There's no way Dana/UFC want anything to do with co-promoting Conor/Mayweather with Mayweather promotions. There's that, and again, Conor is under contract with the UFC, he can't fight anywhere unless it's with the UFC, no matter what (combat) sport it is.
Floyd knows this, but that doesn't mean he can't have some fun for the time being. The shit talking will only hype it up even more if it does happen one day. May as well start as soon as possible to get people interested and build it up over a good stretch of time.
Floyd isn't shook. He knows that it will be settled in the boxing ring, why would he be shook? He's on a completely different level than Conor in boxing, he would pick Conor apart very, very easily and he knows it, and so does Conor, Dana, literally everybody knows it.
Honestly, Conor is just preparing to lose no matter what in terms of the fight, but will be paid very well so that's a win in itself. He'll lose the fight, but make some damn good money doing it. No shame in losing to one of the greatest boxers ever in boxing.
For Floyd to speak out this much lately, it's obvious that he's very interested in making this shit happen.