I always thought it was the perfect solution, if by accident. The network is segmented, and people can connect to who they tolerate. It avoids censorship but still lets people curate their own experience. Win/win.
Gab used to be federated through to Mastodon (not directly of course, but via a hop or two). For some reason they stopped, but there are other "non-conforming" Mastodon instances out there.
I thought so too, until I saw how this works from inside. Segmented networks sound fine in principle, but there's a pathological behavior happening: there's a group of people around the core instances that like to take offense over things, who then try to pressure the administrator of that person's instance to ban that person, or else they'll defederate the whole instance. The source of offense may be some wrongthing the person posted, or reposted from another instance, or any "known association", etc. Also defederation because of incompatible codes of conduct is a thing, and as you expect, this creates a pressure towards CoC extremism.
The Gab thing was funny to watch, lots of people behaving as if that service was a literal existential threat to Fediverse, and banning - or advocating to ban - anything related to it up to two degrees of separation. It also revealed an interesting pattern - Mastodon itself may be decentralized and instances are theoretically independent, but there for sure is a community of Fediverse people that's pretty hiveminded. And left-leaning. Gab definitely wasn't welcome, and wouldn't be able to benefit much from federating through Mastodon, even if technically nobody could stop them.
(To be clear: I don't like Gab, never interacted with it, and I don't particularly care about it. It was just weird to see the degree of moral panic on Mastodon happening the moment they said they are considering joining the network.)
Mastodon is therefore an interesting experiment in how the ideal of distributed web - of virtual archipelago[0] - falls to realpolitik. Freedom of curation is limited by your ability to deal with threats of defederation.
In this sense, when you're switching from Twitter to Mastodon, you're switching from a stable tyranny to highly volatile sorta-democracy. Pick your poison, I guess. I stick to Mastodon, and try not to give the admin a reason to get me banned for going against the party line.
I thought that was the reason they didn't want to do it in the first place. But for whatever reason they changed their mind. Which was good, because I know of at least one instance that did not ban them. Also I think they tried selling the idea of other people running Gab instances to federate with each other. But I guess it was just too much to keep up with or something as they made their own changes to it.
Gab is really scrappy, to say the least. They might hate Silicon Valley but they've most definitely adopted "move fast and break things".