I am inlove w Kazui's lore because it's so good and I relate to it so I'm gonna explain a frame in Cat mv and the correlation with the Mukuhara Gay-zui theory.
In Cat, in the second verse before the bridge, we were shown a scene where Kazui lifts a wine glass to block Hinako. At first we see through it, seeing Hinako staring at Kazui lovingly, but then it cuts to reflecting Kazui. But instead of his head, we see a green apple. (We can confirm this was Kazui's reflection bc it was his bar outfit from half mv)
The apple for the head, i think, is a reference to the "Adam's Apple" painting. Where there is a man standing with his face barely covered by a green apple, but also never revealed.
The painting's meaning was "don't seek what you can't see" and to accept things as it is. Don't think of how the man might've looked like, his expression or anything. And this fits so well into Kazui, who lies and conceals the truth, who he is, and practically telling people to not look for it. To accept it as it is.
The apple immagery has been prominent since the start. Kazui, has always been connected to the green apple. An anomaly within the other red apples. An "other". This is very similar to how the LGBT+ community have been shunned or treated differently by non-LGBT+ people.
But the best part of this apple imagery is that, even with it's different color, at the end they're the same. The same fruit, the same tastes, the same texture, etc. Like even if we don't like the same things, and love the same people, we are still as human as any of them.
Kazui probably, maybe has come to terms with that. The fact that he's gay and that he's the same as any other human being. That's why the mvs show the apples. They reflect the prisoner's mental state and ideology, so the apples definetly reflect how he sees himself and ithers around him.
And that's it for my ted talk, I love Kazui Lore sm guys 😭😭😭