Their biggest complaint was something I found odd as a new user to the fediverse too. When I was looking for a home instance, I saw that beehaw required an application, but I could just create an account elsewhere and interact that way, skipping it.
It seems like (at least one of) the tools they want is to allow federation to other instances, but external accounts must still “apply” before being able to comment or post. That’d allow users on both instances to still view each other’s content, but it’s not as cut-and-dry as blocking all posts from external accounts like limiting would (if implemented) or worse, defederating and siloing from all.
That’s a good point about the user authentication, but I’m not quite sure we’d need it quite yet to reduce spam in this way. It is absolutely something to keep in mind though.
I think the other instances allowing federation in the first place grants “I trust the owner to not impersonate users” part of the chain. In Reddit there’s that trust too, the whole “I trust the admins to NOT edit my comments silently at the database level”…