In this case, that's because he's got rid of his Linkedin account since that article footer was written (I follow Neil via Mastodon, he discussed it there).
If the blog footer is intended to contain links to identity, I'd make that whole footer dynamic and then I'd just keep a single source for that.
Alternatively, arguably better: Keep a master domain for each identity and update social media accounts for that identity on a page in the master domain.
Of course not all lawyers are the same. There are some that really do get tech. Or more like the niche they specialize in, because the days of being a polymath are over, the tech world is way too large and complex these days to know it all.
That said, I thought exactly the same reading the article. If he thinks he's already one of the more tech savvy ones, that only proves the point of the article he's criticizing.
(edited for missing word!)