Harry hated Louis and Louis hated Harry even more. Louis has bullied Harry for about a year now. No one really understands why, Harry mainly. However, Louis maintains a strong grudge against Harry Styles and he is not prepared to let it go any time soon. They were friends right before this, their friendship didn't last long- only a month. Harry assumed it ended because he came out as gay to Louis and his family (Louis was as straight as anyone could get.) So he never asked why and Louis certainly never told him why, either.