This is just a federation protocol, so it doesn't really solve the problem: federated systems are just a way to make it easier to interoperate between a number

This is just a federation protocol, so it doesn't really solve the problem: federated systems are just a way to make it easier to interoperate between a number of separate instances, but every individual "thing" (in this case, a repository) is still going to be hosted on an instance that can be taken down (and sure, it could be put on another one, but then you didn't solve the problem); what you want is a "truly decentralized" (the word "truly" in parentheses was a critical part of the comment you were replying to) and really hopefully "distributed" revision control alternative, not merely a mechanism to "enable interoperability" (the phrasing from their website) between existing services (which should make the issue clear: if no existing service could host the repository in question, then interoperating between existing services doesn't suddenly cause stable hosting to appear).