I think Snape cared for Harry in the fact that Harry was the son of Lily Evans, but Snape absolutely abhorred Harry because Harry was the son of James Potter. In any case, I don’t like Snape’s teaching style in the books either, but I feel like J.K.R. did that to make the readers firmly believe that Snape was evil in order to shock us that in the end, he wasn’t that bad of a guy.