The thing that worries me the most is that there is no public mirror of (important) OSS Github projects outside of the US, is there? It is all centralized in one place under one jurisdiction.
How much in US jurisdiction are they? I do not live in USA and don't want to have anything with that country, specially don't want its long arm of IP law anywhere near me.
Even if github is gone, your local repos are still there and there's very little friction to migrate or push source code to other github alternatives.