Fighters look at this from their own perspective.
From Justin Gaethje's perspective, when a champ retires, the #1 contender should fight for the title. It's a no brainer (to him, who was the #1 contender). If not, why have rankings? So he was pretty distraught when he didn't get it.
Similarly with Tony, he had a certain expectation several times in his career. One was the potential Holloway fight. He wanted it to be for a title, not the interim title. He made such a stink they went with Poirier instead. But that wasn't the only time he expected things to go a certain way, and they didn't. Ultimately he blames Dana because at the end of the day, decisions went across his desk.
I don't agree with Tony, so don't argue with me as if I'm defending him. But I'm pretty sure that's it.