Unifications can sometimes trump mandatories but not always. Certain organisations, IBF especially, are very strict with their mandatories. In this instance Catterall would've agreed to a unification taking place before his mandatory shot as he had been paid to wait.
Fans are fickle but there are fans, like myself, who actually want to see the sport fairly judged and in a transparent manner. It happens far too often where an 'away' fighter gets jobbed on the cards. There's giving a close fight to the home fighter/A-Side and then there is a blatant robbery. I can take a close decision going to the bigger name fighter, it happens. But actual robberies, which there aren't many I think are outright robberies, really rub me the wrong way. Boxing is a brutal sport and in the words of SRL; "You don't play boxing". I want to see all fighters get treated equally and have a fair shake and not be like Canelo in Vegas where he is 4 rounds up before the first bell.
The IOC has their own issues but when even they are stepping away from boxing the organisations need to have a long look at themselves. Boxing really needs an international governing body because it's set up more like a business than an actual sport. That's why boxing is essentially entertainment first rather than sporting excellence because it's not run like a sport at all. Using that as a segue, is why I have no issue with 'YouTuber' boxing, Misfits etc and why I am quite looking forward to watching Jake Paul batter Tommy Fury around the ring.