If you make a lemmy, and the your admin bans you, what happens to it?
Lets say I have an account on lemmy server A, and with my account I make a lemmy community. Some people post in it. Everything is cool. But for whatever reason the admin/owner of the lemmy server your lemmy community is on decides to ban you. What happens to the community you made? How does the lemmy software respond to it? Does your community get banned with you? Or does the community just get stuck without any admin and people can still post in it?
As I understand it, the community would simply carry on without a mod, until such a time that the site admin appointed a new mod. The content would remain, and other users would still be able to post to it etc.
If this concerns you, make your own instance and disable creating new communities. Plenty of instances are doing that to house the content they want and nothing more. Through federation you'd be able to be found and accessed by other instances so users can post and engage, and if you prevent user logins and interact only with your community through that instance user, you'll never have to worry about pulling other federated instance content either.
I think admins can take mod actions on communities on their instance, so they would be able to appoint new mods and do moderation actions in the interim.
It completely removes them from the database instead of leaving a tombstone in place which is usually preferable in a federated network. The purge option was mostly added for legal compliance reasons.