Literally on the second slide: "I’ve done engineering since the turn of the century, and led small teams and biggish orgs."

If that is not navel-gazing or humble bragging, what is?

I would propose to you that those might be factual statements. I don't really see any self-indulgence in stating where one is coming from when writing a post that is a critique of organizations.

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 :)

I‘m sure it‘s factual and common, but it‘s tone-deaf given the slide deck title.