I guess you could also argue it's "sketchy" in the same way, but source code is just source code: it can easily be hosted anywhere, and is probably only marginally more risky than a fork adding malware and hosting it on github. Oh and for the record, sourceforge is pretty much legit again, and has been for a number of years.

If they do end up surviving I would expect it will happen quietly on a self-hosted git instance which will eventually become known as the official repo. But yeah, certainly there is a higher risk of malware and shadiness happening for the forseeable future.