If you actually go to the account description of @[email protected], it says it's an unofficial parrot bot of Microsoft dev blogs. Title seems misleading.
That's because Microsoft isn't officially in the Fediverse (yet), and this is a project Maho - who is a Microsoft employee - did in his spare time. There's also a note there about where to give feedback if you'd like Microsoft to officially have a Fediverse presence.
I'm not sure if Maho is on here himself, but Nick Cosentino - another Microsoft employee, and the 2nd person to follow the bot - is, and I'm sure he'd be happy to clear up anything. :-)
It also doesn't post back to Microsoft's dev blogs. As an example, the Mastodon blog post doesn't contain the comments from Microsoft's post. I wouldn't consider it federation until this is true.