A lot of times in many of Jin Yong's novels, there were martial arts that were considered "evil" or so called evil. For example Sunflower Manual (KHBD) which was destroyed by Ren Woxing, Bixie Jianfa, Xi Xing Da Fa, White Bone Claws of Jiu Yin Zhen Jing, Poisonous Spider techniques used by Yin Li in HSDS and even Hama Gong to some extend.
So the question is, can martial arts really be "evil" in nature? Or is it the practioner that makes it evil?