Definition of witchcraft/Wicca 

I have some problems with this section. It's all very nice to be able to laugh and say "you're wrong on all these points", but in fact this section is misrepresenting Wicca just as much as the Harry-haters.
The heading itself seems to imply that witchcraft and Wicca are synonymous. Wicca is merely one variety of modern witchcraft.
Wiccans commune with the dead and the spirit world. At Halloween (or Samhain), for example, we invite the spirits of our ancestors and deceased loved ones to return and share our warmth and companionship for an evening. Extensive spirit contact by Wiccans (via ouija board and channeling) is recounted in A Voice in the Forest by Jimahl diFiosa, an Alexandrian High Priest.
Sorcery: well, Wiccans definitely perform magic. The word 'sorcery' has a sinister sound to it, which perhaps doesn't fit with Wicca so well, but if it merely means 'performing magic', then certainly.
Occult symbology: this is merely a catch-all phrase for anything that looks a bit 'occult', isn't it? Well, Wicca is very definitely 'occultism', since it deals with magic and the hidden parts of reality. And yes, Wiccans use occult symbols, such as zodiacal signs.
Curses are of course forbidden in Wicca, as is all malicious or harmful magic.
Demon posession: Whoever accused Wiccans of practicing demon posession is pulling a swift one. Wiccans practice what could loosely be called "posession": calling our God or Goddess into the body of a priest or priestess. I guess this is fairly similar to what Christians call "being filled with the spirit", but if you happen to consider the Wiccan gods to be demons (and of course they're demons, aren't they, since any deity other than Jehovah is a demon), then you could term this "demon possession", feeling only a tinge of guilt at your verbal chicanery.

The real reason why Harry Potter has nothing to do with Wicca is because Harry Potter is fantasy, presented in a manner that has virtually no resemblance to the reality of modern witchcraft, whether it be Wicca or any other variety. How many kids watch the Power Rangers and decide they want to enter law enforcement as a ranger when they grow up? The Texas Rangers, just like the Power Rangers, wear uniforms, fight bad guys, protect law and order, have headquarters and so on. The parallels are all there, but any rational person will immediately discern the vast differences.

I don't think we need to misrepresent our religion, simply because some people get the flutters whenever the words 'magic' or 'occult' are mentioned. Lets show a bit of backbone, rather than trying to turn our faith into what we think Christians want it to be! ★