No, it's a misnomer in my opinion. And that hides a rather nasty twist in human relations:

In order to shun someone from a social group due to their non-conforming behaviour, the group cannot simply accept that they are willingly excluding this person. Because that would violate the basic premise upon which the group is built: comradery and loyalty. So the group must rationalize their behaviour by sticking all the blame on the individual being excluded.

You can go medieval and call someone a witch, or just be a bit more moderate and blame them for something vague like having "low self-esteem".

Not wholly, but partially. It doesn't matter much if you believe in yourself when few others do. The social group is more verifying your self-esteem.

I'd say it's easier to rely on external validation in many cultures because anything not well-defined is hard to teach. Poorly defined subjective experiences are even harder.

Of course. Social group influences a lot how you perceive yourself. You can only establish a value of something by comparison.

I'm noticing some language trends in this whole thread worth pointing out:

- In OP, I wrote self-esteem is the root of narcissism, when I really believe it's a potential root. It can also be symptomatic because pretty much everything in the brain can flow both ways, so one person's symptom can be another person's cause.

- We tend to forget the importance of the word "can." I'd rephrase what you wrote as "Social group CAN influence a lot about how you perceive yourself." It doesn't have to.

Also, comparison isn't needed. Here's how I do it:

I recognize a few key facts:

- every person is unique in some way - every unique property of a person reflects something to be learned, even if the lesson is the opposite of said property - neural networks learn and apply learning - we are walking neural networks - the past is changed by observing the present

Therefore, everyone is valuable in some special way, including myself. My self-esteem stems from reminding myself that others' perceptions of my experiences do not define my reality, my value, or my past. Those are all mine to define and nobody else's. I don't need to compare my subjective experience with someone else's in order to value mine.