My guess is to establish the approximate amount of collaboration. He didn't work there full time for years, that collaboration has been small and limited.

It does make one wonder--careless work, trivial problem, reuse of existing projects, writer portrays self as extremely productive, or some combination?

I think you're assuming bad faith from someone who has proven very competent, technical, and coherent.

It might simply be truthful. And if the author is proud of that, it is both irrelevant and perfectly okay. Let's focus on the facts and arguments relevant to the article, not personal attacks.

None of the options I proffered are in the "bad faith" category.

Ya, it's hard to interpret it differently, so was curious. Don't know why I'm being downvoted for a question about rhetorical intention.

I didn’t downvote, but it comes across as a nitpick on a thoughtful and reasonable piece.