De Gale is signed to Fat Mick and Channel 5. Froch is signed to Matchroom and Sky. If the fight was to be made Matchroom would call the shots and Fat Mick/C5 would have to let their guy fight on another promoter's bill/another network. There's zero chance of this happening so De Gale is free to try and generate some publicity for himself by calling Froch out for a fight that can't happen. Expect him to keep doing it every few months, every time he's on the telly basically.