At the old school I went to...christian school...fundies here in texas all think HP is evil.
Yet, most of them watch Cindarella, Snow White, Pinnoccio, ect...all have magic, too, and its really -exactly- the same. People who have never read harry potter, however, enjoy talking about bad it is...
I don't see what's wrong with watching movies with things you don't "believe" in...I mean, do you believe there's really some land somewhere where Jerry and Elaine hang out? Or where Ninja's are turned into mutants and fight crime?
Its just imagination...the people who watch it don't "believe" it, either, they have enjoy watching it. Its fantasy.