I can, but it would still be effective for public announcements because Mastodon does not typically require a login to view on the web, and it provides am RSS feed. Walled garden platforms that won't show posts to anonymous web visitors are not acceptable for public announcements.
Surely there are plenty of people who could be hired to make that not an issue? The same argument could be used for other government services. In the UK you do a lot of things through gov.uk. we also had a vaccine passport system as well which is arguably more important than a mastodon instance.