Well, that's the thing, from what I've heard and observed it seems like narcissists don't necessarily 'enjoy' hurting others, but rather that they have their own heightened needs for admiration and attention. They prioritize fulfilling those needs over being a nice person when they can't have both. And that's when they start being hurtful. Doesn't make them good people just highlights that there's a lot more impulsive, destructive behavior to narcissism rather than careful planning to actually hurt someone.
Which is why sociopathy is so interesting, because these people actually seem to enjoy manipulating others. They might not necessarily be out to hurt you, but then they don't really know what hurt feels like, so they'll probably hurt anyway you while playing their game.
Also, it's obvious that someone can have both narcissistic and sociopathic traits as they complement each other quite nicely