Promoter Frank Warren says Tyson Fury had been "training like a demon" and it is "ridiculous" to question the legitimacy of the Briton's eye injury.
Heavyweight Fury, 35, had been due to fight Oleksandr Usyk on 17 February but withdrew from the contest after sustaining a cut in sparring.
The undisputed title fight has been rescheduled for 18 May in Saudi Arabia.
"Tyson wants [the fight]. Some of the stuff that's been going out, I've never heard anything like it," Warren said.
Fury is the WBC champion while Ukraine's Usyk, 37, holds the WBA, WBO and IBF titles.
Their bout in Riyadh is set to crown the first undisputed heavyweight champion in the four-belt era.
"I don't understand how these people get living out of this game," Warren said of those questioning Fury.
"Has Tyson got make-believe stiches in his eye? What they're saying is libellous and scandalous."
Speaking to Steve Bunce on the 5 Live Boxing podcast, the Queensberry promoter added: "It's like some kind of cult against him."
Fury's cut above his right eye required "urgent medical attention" and "significant stitching". It is the third time since 2023 a fight date between Usyk and Fury has been rescheduled.
Just 24 hours after news of Fury's injury broke, Saudi Arabian organisers and Team Fury moved quickly to secure a new date.
Fury had been training in Saudi since the start of 2024 but Warren says the Morecambe fighter will now return to the United Kingdom as part of his rehabilitation.
"He'll want to be with his family," Warren added.
"He can't continue training as such. He can tick over. He can get on the bike and keep well but when you're training for a fight you're training to reach your ultimate best, your peak.
"Now he has to wind down and set everything back in motion to get himself up and ready and make sure he's at his best for 18 May."