Could you elaborate on what is HN if not things that hackers find interesting (particularly "very interesting")?
In my opinion something is on-topic if most hackers would find it interesting, and most non-hackers would not. Otherwise you might as well just drop the "Hacker", and call it "News".
Very true, but then much of the marketing and entrepreneurial fluff that gets posted here is neither news, hacking, or especially useful from a business standpoint. A few people treat HN as their personal viral marketing vector.
I believe the referenced story qualifies under that metric. In part, it's revisionist history -- and thereby anti-mainstream. And I very much doubt that the TMZ crowd would even be interested in parsing stories told from such a business/technical perspective. But that's neither here nor there.
In all actuality, I do sympathize with the rational for your proposed metric. I'm just pointing out that the nuance and angle of a story can push something distinctly into that category in cases where simply reading the title might lead one to have a "Not HN!" spasm.
In my opinion something is on-topic if most hackers would find it interesting, and most non-hackers would not. Otherwise you might as well just drop the "Hacker", and call it "News".