Okay i have no patience SO
Fundamentally, when you look at Rollo’s interactions with Yuu and Malleus, it seems to me that they embody different aspects of his inspiration’s obsession with Esmerelda and desire to either have her, or kill her so no one else can have the privilege to be “ensnared by her spell”. Madonna-Whore may not be the best way to describe it, but its what my brain is sticking to because i am sleepy.
Malleus is very obviously the latter embodiment—he is one of the five most powerful magical beings in Twisted Wonderland, whose presence is so integral to Rollo’s ambitions that when he isn’t selected by lottery (i think if im wrong im sorry), Rollo extends a personal invitation to ensure he will be there when the red flowers bloom. Malleus is, in many ways, the very essence of magic in the story of Twst, fantastical, capricious, slightly removed from the experiences of regular people, capable both of impetuous extraordinary kindness and of impetuous inescapable devastation. He is utterly reviled by Rollo, even as there’s an undercurrent of fascination (especially towards the end of the Glorious Masquerade storyline—it seems dark hair and green eyes are a lure he could never hope to escape). Malleus is a symbol of everything Rollo feels is wrong with the world and wants to stamp out, even as part of him reveres it like he does the Dark Mirror and the Bell of Solace. What a shame such a beautiful being must come from something Rollo despises so.
Yuu, on the other hand, is idolized by Rollo almost from the moment he learns of their origins. They are completely uninvited, only sent along by Crowley at the last minute, but you almost couldn’t tell from Rollo’s near uncharacteristic gallantry towards them, which is heavily contrasted by his cold politesse to the rest of the NRC students. It quickly becomes very apparent that they are as a Madonna in his eyes, a “pure” being wholly untouched by the magic that infests every other part of his world, a literal manifestation of the ideals he’s held for so long…
Which is why it is so devastating to him when Yuu turns around and tells him that they’re fine with magic.
How could it not be? This is the only “pure” person in his eyes telling him that magic is not an infestation or a corruption, a plague that he must purge from the world by any means necessary, but something that can bring joy to them and to others. Even if the more neutral option is chosen, treating magic as something that is more of a tool than an outright evil force is a seriously threat to Rollo’s worldview. Because of course, if it is a tool with no inherent morality, only reflective of the choices its wielders make…but that cannot be. No, the only explanation is that Yuu must be corrupted, tainted even by their proximity to those despised magic users—the hateful Malleus Draconia most of all (remember, in the scene beforehand, we get to see Malleus and Yuu’s friendship and their desire to sit together to enjoy the festivities). No, Rollo vows, one way or another, Yuu will come to the light and either be saved by seeing things his way or they will perish with the magic users they insist on cavorting with.
Which, of course, does mirror the “marry me or you will burn” rhetoric Frollo threatens Esmerelda with, but in my mind there are also some parallels to the relationship Frollo has with Phoebus. The shining captain of the guard, meant to be the enforcer of Frollo’s crusade, who as the film goes on constantly disappoints the judge by being too human to go along with his cruelties, who actively takes a stand against him and tries to save the very people he is employed to destroy. A handsome man in golden armor, Phoebus is much more the picture of a divine champion than Frollo could even be, so do you think it stung? When this man, who could be called an instrument of Frollo’s will as Frollo is meant to be an instrument of God’s, looks him in the eye and tells him “no”? Tells him that his prejudices don’t trump the right people have to exist? Do you think Yuu’s rejection hit Rollo in the same way?
Tl;dr Rollo is a disaster of a human whose prejudiced obsessions mean he can’t rid himself of Malleus Draconia, nor can he gain the regard of the magicless Prefect.