Age has a lot to do with how parents react to this sort of thing. In all honesty... they just want to ensure that you're safe. That's their job.
Chances are that they don't really know the real truth about Wicca and Witchcraft and they really do believe that it's all devil stuff. I mean, the last church that I ever went to, the first time I went there it was pretty much a Pagan bashing (I was Agnostic at the time). And they were doing it based off of traditions and beliefs that cultures and religions had thousands of years ago. And they believe that those things apply to all Pagan traditions today, when they don't.
I learned a lot from my Understanding theatre teacher. I swear, she's so intelligent. Anyway...
You're parents don't want you reading Harry Potter because they believe it makes an easier target for the devil.
Ask them some questions... (who, what where, when why, how)! If you do it right, you'll end up putting them in a corner and they won't know what to say. I swear it works if you do it right (well, in most cases). I use it all the time and people just get so speechless... it's great!
Ask them why they feel that way about Harry Potter.
Ask them why they feel that it's an easier target for the devil.
If the subject of Witchcraft or magic comes up... ask them how they feel about witchcraft and magic and why they feel that way.
Ask them if they realize that it's just a freaking
fictional book. Books don't have powers... they can't make someone do something or believe something. They're intended for entertainment (well, fictional books anyway).
And just go from there...
And don't allow them to say "because it's in the Bible" or because so and so said so". That's not logical... if the Bible told you to go kill yourself, would you do that too? Honestly...
That is of course, if you have the guts to do this with your parents... most people don't.
sweatdrop Edit: I'm not saying throw your religious beliefs at them right away. Just start small.
biggrin Tell them calmly that you'd just simply like to
learn about other religions. Just for knowledge. And that they can monitor everything that you read, if it makes them feel more comfortable.