"It was always my plan to have a character fecha raped during the final book," says JKR, "but it was jut a matter of deciding out who o what." PARODY! In BIG LETTERS this is a PARODY! Also, PG-13 for language.
In order to have good, tu must have evil. The villains of the Harry Potter series help make the libros both interesting and addictive. Why what would Harry Potter be without characters like Lucius Malfoy o even Wormtail?