Harry isn’t exactly the most thoughtful boy at Truham. He bullies Charlie (and his friends) and deploys “jokes” to hurt the people around him. The reason Harry hates Charlie is because one time young Charlie reportedly accidentally hit Harry's face with a shovel very hard in the school yard and it ended in a hospital visit. He, at least on the surface, is popular, but quite homophobic and mean, throwing insults disguised as jokes. He has over 20k insta followers.