It's interesting how Oniwa, instead of just being an introvert, was just anxious of speaking because of his friends from middle school, specially when you take into account that he has shown that he's perfectly capable of carrying a conversation with the club members.
Naturally, not only he's at an age where peer feedback can greatly affect you, but it's also related to how one tends to talk or act in a way that feels totally natural for them but not for the others (or at least not from people outside of one's own group), which constantly takes them aback.
Thanks for the chapter.