I’m not saying there shouldn’t be any moderation. But there’s a difference between deleting a post and preventing whole communities to be accessed because of a subjective sense of what is the correct viewpoint on [topic], be it political, ideological or else.
I could imagine a setting where other instances’ posts/communities aren’t shown on the All page, but could still be subscribed / viewed by the user if he requests it.
This is indeed a difficult problem. Especially as laws and their interpretation are highly dependent on the hosting location.
Hiding posts behind warnings or only showing them only on user request are on the top of my head.