If it's a 'biker's only' campsite yeah fairy nuff.......but if you were runnning/setting up a campsite, particularly as a new enterprise and double particularly in a beaurocracy ridden country like France, is that commercially viable???
I doubt it..unless you have connections and superb marketing contacts.....otherwise, starting off as a decent, biker and family friendly site to get established then perhaps after a year or two once the word is around foccussing more on bikes would have to be the sensible way to go.
Just the fact that a site is prepared to take groups of riders would be enough of a USP to get going I'd have thought....too many places turn you away if they even think you're in any sort of group, let alone tag the name 'biker' onto the group, regardless of whether the 'group' is largely mature, sensible, BMW riding folk and not hairy arsed stud wearing leather clad oiks on noisy dog bikes.
( we got turned away from a site this year...8 30-40 somethings, complete with two toddlers and not a shred of oikiness about us, turned up in cars hoping for a weekend of walking, pub grub and a quiet drink around the trangia...the bloke who owned the site was so anti 'group' that he was rabid.....)