Comment by TFNA

Mastodon 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.