None of those are requirements to be part of the fediverse.

They are de-facto values of the fediverse today. It depends what you mean by "requirements". Technically, you can join the fediverse in many ways, but the fediverse is not just a bunch of servers talking to each other, it's also a community of people. This community rejects some members for different reasons.

there’s multiple companies invested in the fediverse: Mozilla, Flipboard, Facebook, Automatic being the most obvious.

But those companies are very different, aren't they? Mozilla and Flipboard are participating within the fediverse, they are not plugging in their things, and their business models are not the same as Meta, and it is compatible with the values mentioned (well, Mozilla is a no-profit, in theory?). Wordpress is on the other hand very much aligned with the values of the fediverse. It is not the same as Meta and Bsky, both with the Silicon Valley DNA in them and all that it entails.

Truth Social, Gab, Spinster, etc are all on the fediverse despite being abhorrent to the majority of the rest of the fediverse.

And this is exactly where I disagree. Are they part of the fediverse? I wouldn't say so. They are completely isolated islands, that happen to use protocols that are similar to those used from the fediverse (software). They are not part of the fediverse if by that we mean the set of communities that populate it at all.

I suppose this is where the root of our disagreement lies. For me the technical network that links tools is not the fediverse. The fediverse is what is built on top of that network and it is inherently linked with the community and their values, in other words, it's a social subject. Personally, I can't care less if tomorrow anybody starts using AP and can (technically) interoperate with Lemmy or Mastodon etc., I would definitely push for the rejection of - say - Facebook (like the literal facebook) or Reddit, or Twitter etc.