I have no idea who most of the authors of essays submitted to HN are. Sometimes I come to know more about them by reading more of their work, but usually I don't know who they are before then. Same for the vast majority of folks posting comments.
If we are interested only in the opinions of people we already know, how can a site like HN even exist?
I mean its not bad. I agree with your original statement that I too, don't know the majority of people who post stuff to HN in general, and I don't have issues with that. However, when someone submits a name in the title, I expect it to be a name that is relevant or something I would consider important. Names like Marc Andreesen or whoever makes a lot of sense. Wil Wheaton, not so much. Of course thats personal opinion.
That said, even with blog posts by Marc Andreesen, you don't see stuff like "<insert name>: title". That sorta irks me. Personal problem, I know.
If we are interested only in the opinions of people we already know, how can a site like HN even exist?