Not all self promotion is good self promotion. I've nuked candidates because their online portfolios demonstrate bad technical judgement, questionable professional ethics, a fundamental misunderstanding of core ideas, etc.

Put more simply: a portfolio is a demonstration of your work. Anything you put out in public with your name on it is part of your portfolio. Obviously, don't put bad work in your public portfolio.

There's a reason you see very few serious data scientists publishing hot takes on their medium blogs -- it's a serious threat to your professional integrity and brand if you get it wrong. The only people I know & respect who are writing publicly about this topic have SME collaborators. (Of course, we're all playing with the data and talking about it in private with friends/coworkers over coffee.)

Self promotion specifically by spreading your amateur take on a health crisis seems a bit... immoral? Or at least the sort of thing that makes me question the candidate's judgement.

If you want to write publicly and in a formal way on this topic, get a subject matter expert to serve as a co-author. Anything less is more risky than it's worth, even from a purely selfish perspective.