alt Hacker NewsMastodon devs have said many times that the mainstream fediverse, the original community that federates among itself, has a distinct culture and values that they wish to maintain in perpetuity. That is "policies". Yes, the tech allows parallel ecosystems of servers that don't federate with that original community, but when people talk about "Mastodon" like the OP did, they aren't talking about offshoot ecosystems.
They can say whatever they want but they have no control over it. That's the benefit of a truly decentralised network and free open source software.
It's like Microsoft saying they want a distinct culture among the users of their software. They can want it but it's not gonna happen. Within the mastodon community there's also a lot of servers that won't federate, for example the Germans always have very strict rules that they try to impose on everyone else. So most of the world does not federate with them anymore. *)
I mean there's even stuff like gab and truth social that run on fediverse tech. Not sure if it's mastodon itself or another implementation but that doesn't really matter. They certainly don't meet those culture and values.
And there is no 'mainstream fediverse'. Nothing about fediverse is mainstream to begin with. Unfortunately.
*) Don't get me wrong, I'm very progessive myself but the way the German fediverse community goes about it is wrong. "Follow exactly our rules otherwise you are defederated". That doesn't fly even if I agree with most of those rules.