well the point there is why has she chosen WITCHES, universally thought to be evil and occult to MAKE into good guys. that itself is part of the problem. Cowboys connote nothing one way or the other as far as moral value goes.
She didnt. Much like Tolkein did, she created a world that doesnt exist (though not on the level he did), But the good guys, and the bad guys have the same arsenal.
I mean..Is it a little more compatable, if the Witches are bad, and the good comes from somewhere else, ala Lewis' White Witch, sure.....
But IMHO, to be procedding in this direction gives the Rowling books the heady scent of official disaproval, and by extension detracts from the message you want to send to those very people reading the books.
It would have been far more useflul to say, "They are Kids books..no more no less, and not a problem as long as youngsters are provided with sound moral instruction...'