Gregory's ServerOne criteria I would add to that chart would be "is it #AltText/Voiceover friendly?" I know Mastodon allows visually impaired users to hear text, and the culture here promotes lots of AltText inclusion. Technically, AltText is possible on the Bird Site, but I haven't checked to see if folks include it often.
@TheManyVoices Difficult to include in the table, I wanted to keep it simple. All of these services provide alt text. It's true that only Mastodon succeeds in having it built-in the conduct and culture as well.