I think it blends the line a bit the more you know someone. There are selfish things that you can do without it being narcissistic and everyone can get to a point where from the outside it looks selfish, but context changes that calculation.

Whenever someone is selfish and throws me under the bus or asks for far more than what they give I try my best to come up with excuses for them. Usually this is the right approach and saves me from making an ass out of myself and allows me to "be there" for more people who truly need it, but sometimes I'm searching for that excuse so long or gaslight myself into thinking up a good excuse and I end up as a narcissist's host for a while.

Personally, evil has to be clear, even when devoid of nuance or context.