No matter how far to the right a group of fundamentalists may be, they will invariably be able to find a group even further off the map than they are to point to as the ‘real crazy’ fundamentalists. Whether it be dress codes, music standards, or theological vagaries, there’s always someone else who’s so much nuttier that by comparison even strict fundies look downright moderate.
Question a fundy about their rantings against Harry Potter books and they’ll point you to folks who don’t read anything but Christian fiction. They in turn will point you to a group who only allow their children to read approved biographies of missionaries. And even they will no doubt be able to dredge up some remaining Abecedarians to prove that by comparison allowing reading at all proves that one is reasonable and normal.
Compared to all that, just cutting out Harry Potter seems downright ecumenical. In the land of the full-bore crazies the only slightly unusual man is king.