> In what way is Matt Levine an influencer?

You could argue his job is influencing people.

> He’s a salaried columnist for a news organization.

In other words, he gets paid to influence people on behalf of a major news publication.

I posit that "influencer" is the general term for celebrities, politicians, journalists, priests, etc. Matt Levine is a traditional media influencer. The pope is a religious influencer. Biden is a political influencer. So on and so forth. The modern social media influencers are really independent influencers as they don't belong to a corporate, political or religious entity.