Why would Robbie turn that fight down? He'd be fighting a much smaller guy and as hard as he hits, definitely the hardest hitter Conor's faced, he's got a better than average chance. I personally think Robbie would be too strong for Conor in every area.
It would definitely be a huge money fight and Robbie would definitely be super confident about it, so I'm not surprised he'd agree.
Now Conor being dillusional enough to ask for that fight is another matter. I think that a fight with Robbie would hurt him, and not just physically. He'd more than likely lose and the way Robbie hits coupled with his ability to take massive punishment from guys much larger than Conor, it might be one of those fights that changes a guy forever. Like Cain vs JDS II and III, Junior's not the same guy now. I think Conor would lose and lose badly, which would hurt his invincible image he's crafted. I feel he's already playing with fire by fighting RDA, so why take a bigger risk when he wouldn't need to?