it’s partly because everything has public/private certificates, but also partly because there isn’t much synchronization going on after the initial “push”. if you shut an instance down and modify the database directly without informing other instances (say, you remove an account) then other instances will not be able to tell and will drift out of date, essentially making that specific thing unusable for any instance that has previously interacted with it. if you expand that out to, say, wiping and re-creating an entire database, then you end up with so much uncertainty that you may as well start over from a fresh domain