Absolutely.

No one pretends the Harry Potter books are real.

Children do! Through the power of imagination!

What is your explanation for how man came to be in his current form?

Short form for the ADHD:
Man is here from:
A ) creation
B ) macro-evolution

I'll stick with the DNA and fossil evidence and go with "evolution".

...go to a Harry Potter convention and get back to me on that .

So, you believe we evolved, including our brains. You contend that those with religion believe it as a fairy tale, a fancy, that their brains cannot be trusted. I contend the same for you and your brain, it is equally as delusional, and therefore your beliefs are just as ridiculous and foolish. Your thoughts and brain cannot be trusted any more than those of a man that believes in religion, because it quite rightly could be lying to you by presenting you with false facts.

apart from the fact that this books format is clearly not that of a " story "
if that harry potter book is presented by their parents as fact , and not " make beleive " , then ......

With you, yes it is.

...then what ?

Is a Wiccan free to teach their child that witches are real ?