Kiyotaka Ayanokoji was raised in the White Room, a secret facility that was ran by his father, who subjected children to intense physical and mental training from infancy. The facility eliminated emotional warmth and treating people as tools for survival. He enrolled in Advanced Nurturing High School to experience freedom and live quietly away from his father's control.
He intentionally scored 50 out of 100 on every subject during his entrance exam to blend in, initially placing him in Class 1-D. Despite his outward appearence of being an ordinary and unassuming student, he possesses genius-level intellect, elite physical conditioning, and mastery in martial arts. He maintains a calm, indifferent, and calculating demeanor, often manipulating situations from behind the scenes.
The reasons why the fans are cornballs are because they enjoy his deadpan and cold demeanor, completely antisocial, ignoring people, or staring blankly makes him overpowering. They unironically post cringeworthy TikToks or tweets about how they view their high school classmates or coworkers as mere tools and that all matters in victory. They speak in a flat and deeper voice to capture his anime dub presence during casual conversations.
So, yes, these fans are annoying-ahh cornballs. And that's the end to the TLDR.