Yeah, it's federated, meaning you can subscribe to each of them and post to whichever one you fancy. If you want to post to multiple, it's a good idea to use the cross-post feature.
Having only one singular official community would be rather bad, as then the respective server owners and moderators would have central control like on Reddit.
As a German, well, I don't understand enough about the US side of things to answer to this, but I do always get spooked when I see nations pulling shit like that.
And, by the way, I do hope the USA finally get 9/11 under wraps this year: https://www.whitehouse.gov/briefing-room/presidential-actions/2023/09/07/notice-on-the-continuation-of-the-national-emergency-with-respect-to-certain-terrorist-attacks-3/