In many cases it should be fine to point them all at the same server. You’ll just need to make sure there aren’t any collisions between schema/table names.

That’s not the actual reason. Hexbear was openly advocating for their “army” to brigade other instances once it was federating. It just so happens that the basis of that brigading was going to be political.

Lemmy.world pre-emptivly decided it wasn’t worth the hassle of having to deal with that.