Is this article/nytimes.com part of the Fediverse? Yes
FTFY. Problem solved.
if we speak about the Fediverse we mostly mean social networks like Mastodon and Lemmy.
I don’t know who this “we” is but I don’t. The Wikipedia article has a couple of good diagrams showing what most people consider to be the Fediverse - sure it includes the big dogs like Lemmy and Mastodon but it includes Wordpress and Diaspora (still need to dig out my old Diaspora account).