That may be true, HOWEVER, Severus went to great lengths to protect Harry until he was ready to fight Voldemort. The way I see it, Snape never hated Harry. Snape being mean to Harry was just an act in my eyes, so that he could play his "devotion to Voldemort" even better. In the end, Severus did all he could to protect Harry just because of Lily. I think that means something.