Federation at its core promotes echo chambers because instance admins can just defed from any instances that popularly have different opinions. But it's also a benefit because really safe spaces are also just echo chambers (and less extremely just "a place where you don't have to argue with nazis" means shutting out some opinions) and they have their place because sometimes you just don't want to deal with the world's bullshit.
The nice thing is that you can choose an instance that fits your own needs for that and still interact with others that prefer different moderation, so long as your own instance isn't part of the defed list. So if someone wants to argue with nazis but still participate in idk lgbt spaces, they can, and the nazis still won't bother the lgbt space.
And if everything fails, you can also host your own.
The good thing is that all sane instances can just defederate and we won't have to deal with them. They can use the software all they want, and we can shut them out from our spaces all we want.