One thing we often hear about Cluster B Vampires is how they lack empathy. One of the things that makes many of these emotional vampires fly underneath our radars is that we can remember instances of them displaying what seemed like empathy. The inability to reconcile these instances of supposed empathy with their other narcissistic and destructive behaviors often causes cognitive dissonance in us. I think there are two simple explanations for this incongruity. First, they learn how to fake empathy by studying the appropriate reactions of others. They never learn to truly feel empathy, but they learn to act empathetic, the way a person masters a script or a dance routine. The other explanation is that what you were witnessing was genuine, but it was sympathy rather than empathy. Narcissists feel emotions in a shallow and caricatured way, and many times (not always!) sympathy can be a shallow and caricatured analogue to empathy. Sympathy is a much easier emotional state to achieve.
I think something else to take into account is that not only do narcissists and other emotional vampires find sympathy easier to accomplish than empathy, but also significantly more attractive and reinforcing to their narcissism. See, empathy involves you lowering yourself to a person’s level and admitting that you have felt the way that person has felt in the past, that you have been in their shoes. It makes you less special and unique. Not being deemed superior even for a moment is devastating to a narcissist. Sympathy however actually elevates you above the target of your sympathy. Sympathy isn’t inherently bad, but when misused it can allow one to condescend to others and look down on them.
This metaphorical story (or allegory, I’m not sure) by Brene Brown really drives the point home: