There is a categorical difference between having empathy for another person on the one hand and granting empathy for another person relevance in a discussion of the objective morality of that very person’s chosen actions on the other hand. Granting empathy such relevance – in other words discussing how empathetic we are to the other person or discussing how culpable the other person is for the moral wrong of his actions – is only “helpful” after everyone has agreed on the objective moral standing of the particular chosen actions at hand.
Now, with that out of the way, a word about empathy. It is understandable that we are empathetic to those that we are more naturally inclined to have sympathy for. For instance, our fellow countrymen or those in similar social standings or individuals who overcome great personal difficulties or experienced great personal anguish. However, if we allow empathy to play dice we should be careful not to carve out certain people deserving of empathy in isolation of others who can be cast aside. In fact, it can be rather instructive to ask ourselves why, exactly, we more easily empathize with certain people.
Empathy is no one way street. So, whenever we are discussing empathy for a person who has committed a grave moral wrong it is always fine to ask ourselves: “and what about the other guy.” We may have empathy for someone who has committed an atrocious evil, such as murder. But we should never allow ourselves to become trapped in an empathy silo that would prevent some empathy for the murdered.