This is interesting.
As for the "glasses": in the story, it's spelled out that Kurokawa's in love with Fujishiro as well but yeah as pointed out by others already it's riddled with inferiority complex.
Kurokawa seems to double down on driving home the point to Fujishiro by re-gaining her old mark. She is what she is: lightyears away from the hot stuff. Can't blame her though for feeling that way. When you've set yourself up as a nobody and you're relentlessly bullied i.e "you will never become a princess", being friends with THE princess is an actual miracle. And miracles, normally, are seen as "undeserved". You'd rather love your muse from afar.
Self-abasement sometimes can be a form of pleasure, but this isn't BDSM. Kurokawa's image of herself is extremely unhealthy. I mean it has reached the point where Kurokawa would rather have someone else act out her romantic feelings for Fujishiro i.e her initial shipping of Izumi X Fujishiro than be involved. "She was the one", "Someone who was equal to her" aren't the words Kurokawa uses for herself and instead she uses them to mean Izumi.
Good luck, Fujishiro. She's gotta be the decisive one cuz sure as hell Kurokawa's friggin stubborn here. I just hope she reads between the lines and see Kurokawa's also in love with her.