This is a very late comment, but I've been pondering on your post on and off over the last few days and would like to ramble on a bit about it, and hope you don't mind. I agree enormously with what lunacy said above. But further on JKR liking bad boys, or a specific type of bad boys, well, I think she likes people, and all people are a bit bad, which maybe will turn out to be important in the end. Is her relish in people - in her characters - really at odds with the purpose of her project, as I think you're saying in your last paragraph? Isn't HP a story whose moral is not some version of 'be good' but rather 'be human'? Voldemort, in his pursuit of immortality by way of murder is denying his humanity. In a way Dumbledore too denied his humanity in devising his plan for Harry. One interesting aspect of the bad or wrong actions of the good guys - or the Gryffindors and Marauders - is that through them we are led to sympathise with the bad guys - to see them as human. Most of fandom gets that Harry needs to understand and sympathise with Draco and Snape before he can vanquish Voldemort, but this is less a question of good and evil, right and wrong than it is of common humanity. The corollary to it would be that Draco and Snape need to understand and sympathise with Harry, or remain forever incomplete.