as someone who was in gojo's shoes, people hating non-chan so much looks ridiculous to me. if i'm not wrong, she was the girl that told gojo he was disgusting for liking hina dolls. i agree she said a horrible thing, but... she was a kid herself... all of us said mean things to other children when we were little without realising that our words can cause them so much long-lasting harm. i will totally side with gojo if he won't make up with her, but she hasn't done anything horrible enough to be hated to this degree
(let's see what she does in the next chapters though)
just dreamt it was actually mashima's younger brother (??) because there's no way this is mashima