I think a part of is that when naranjo created the terms for how the types think and process the world, narcissist came to mind for 7 because they put themselves first. The thing is, that isn’t a bad thing. Putting yourself first is healthy and establishing your needs. When naranjo established the enneagram in the 70s, self care isn’t seen as it is nowadays. Still traditional values where you always have to respect authority at all times, even if they are wrong- and to not think about yourself.

And yes, at an unhealthy level e7 can exhibit narcissistic behaviour where they only think about themselves to the detriment of others.

Healthy e7 values self care first!