He discredits himself by doing all that. Calling Usyk a small man and a middle weight. In the lower weights we all call out weight bullies who drain themselves to have a advantage. Fury who's in a division with no limit seems proud of it even though he knows if he was the same size a Usyk he wouldn't be champ, maybe barley a top 10 as well.
I think he's just trolling and clowning them, getting under their skin. He's beaten bigger heavy's like Wilder, Wallin and Wlad and AJ doesn't seem to want any part of him. Joyce turned out to be all hype. It may also be a bit of whistling in the graveyard...maybe he isn't as confident in his ability to beat Usyk as he pretends?