What can be done about it?

Facebook could have been held responsible for its contribution to the genocide in Myanmar

https://systemicjustice.org/article/facebook-and-genocide-ho...

but people in Myanmar could have ran their own Mastodon instance and nobody in the Mastodon community could have stopped them. (e.g. true for any kind of open source software, say phpBB) Whether they federated with anyone else is beside the point because it is an isolated language community.