I get your point about the trans community. We absolutely need safe spaces for trans people. I’m not opposed to the idea of a sheltered community for vulnerable or harassed people (and in fact, for years, Mastodon was mainly a safe haven for trans people who were harassed on Twitter: Mastodon’s history is steeped in trans culture).
But I would understand this kind of aggressive defederation from an hypothetical mastodon.trans or from an explicitly lgbtq instance. Just not from mastodon.art, that’s it.
Then there’s Beehaw here on Lemmy. Some observations could apply to it too, but the situation is kind of different