People use this community, among other things, to stay informed about what's happening with open source software. rsync, possibly among the top 0.1% of software used for system administration in Linux land, starting to use AI in its development is certainly noteworthy. Linking to an issue where people can voice their (anti-AI) opinion, contained within that one issue, is hardly worth getting upset over. Unless.. you know.. you'd rather people stand by and let it happen.

I think it's better to try and convince the developers to pivot away from AI. Only if that doesn't work out, does it make sense to consider a fork. Forks do mean more work overall, still done for free, and the new maintainers will not have the same experience, as you said yourself.