Then I’m afraid he is mistaken. There is barely any real Latin in HP. This is nothing more than an appeal to authority and I even question your source’s authority.
If you don’t want to read HP, that is entirely up to you, but these tiresome attacks, many which seem either paranoid or bizarre, are deeply unfair. And as I said elsewhere, magic is a significant part of European literature, even in the Christian period. You might as well call Sleeping Beauty, Hansel and Gretel or Snow White, or heck, Cinderella demonic because all these traditional stories contain witches or faery god mothers who exhibit magic, even sorcerous powers.