You make some interesting points JB...
As you say Harry Potter makes no mention of the Rede, the Sabbats etc etc... but Wicca is not the only form of Witchcraft nor is it even the only form of Neo-Pagan Witchcraft... My old Coven did not practice the Wiccan Rede and in fact 'The Rite of Vengence' was officially accepted into the Coven's 'Book of Shadows'. This was even reflected in the Coven's Motto: "Sic Gorgiamus Alius Subjectatus Nunc" ("We Gladly Devour All those Who Would Subdue Us")...
I personally think much more is made of Harry Potter than is neccessary - others will disagree - but as I said that's my personal view...
It has SOME impact however... in much the same way as TV shows and movies like Charmed, The Craft et al...
When I was HP of a Coven here in Western Australia out of every 100 enquiries re Coven membership only a handful were NOT from teenaged girls who wanted to be like Willow from Buffy the Vampire Slayer or Shannon Doherty from Charmed... Yes it is a false view of Wicca and Neo-Pagan Witchcraft and certainly not what my Coven was about... but that's what they were after and to a large extent the likes of $ilver Ravenwolf and Fiona Horne catered for them and lined their pockets with the proceeds...
In much the same way, when Oberon Zell (founder of Chucrch of All Worlds) is putting out stuff like this...
http://www.amazon.com/exec/obidos/tg/detail/-/1564147118/qid=1114144249/sr=8-1/ref=pd_csp_1/103-8310467-2099831?v=glance&s=books&n=507846
http://www.greyschool.com/main.asp
To say harry potter has NO effect ... well... it kinda rings hollow now-a-days...
I must admit that with Hogwart's being such AGGRESSIVELY protected trademark (HP fan-sites are always being shut down for copyright breaches) old Oberon has been quite clever in his presentation of his Hogwarts 'clone' "School of Wizardry" and - dare I say specific - in his 'target audience'...
Must be really miffed about all that lost income from potential CAW memberships that $ilver Ravenwolf and Fiona Horne nabbed by NOT larfing at those teenies that liked the Craft and Charmed et al and wanted to be "just like Shannon Doherty"...