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.

Gargron, Apple, Google, all has/had policies for Mastodon, which were incompatible with more than 2/3 of its users(at peak).

> Every instance has their own policies. That's the strength of mastodon.

And its biggest weakness because instance admins keep bitchfighting with each other, holding their users hostage.

That is emphatically the weakness as well. I too loved the idea of "they all have their own policies," until it came to be that those policies ended up being utterly childish "I'm taking my ball and going home the second anyone says any little thing I don't like."