ffmpeg / libav had lots of bad blood long before the fork, which might have been the real driver for making it a "debacle".
GitHub in particular has a "fork" button to make it super-easy. So fork, do your edits. If you want, make a pull request with the original project. If they take it, great: the fork can cease to exist.
If they don't want to merge it don't take it personally but go your own merry ways. And this is what didn't happen with actix.
It is indeed a very sad day. Personally I enjoyed being a small part of this community and amazed how welcoming and constructive it was. But yeah as we grow, we are bound to face this.