The thing that pushed me over the edge was banning of accounts that promoted other social media platforms.

This is a clear violation of what Musk has expressed his view of free speech absolutism is: maximum free speech within constraints of the law and safety.

There's no safety concern here, there's no law concern here. That policy was pure censorship. Of course he has the right to do that, it's his platform, but I found it wildly hypocritical.

The value proposition of Mastodon is that it's distributed and censorship can only exist at a federated level. If you don't like it, you can move servers.