I don't see what you see. Would you mind what part of this seems pretentious, navel-gazing, ignorant? ( I think rambling was stated in the article :)
If that is not navel-gazing or humble bragging, what is?
It is a pretty common thing for people giving a talk to introduce themselves to give an idea of the experience on which the information that follows is built, normally at much more length.
I don't think it is uncommon for people on HN to have led small teams or biggish orgs :)