@Jo TL;DR: years of moderation and governance issues going unresolved, environment having become unworkable, volunteers leaving over it, and a fork seems imminent if there is no rapid solution.

I wouldn't recommend diving into the details unless you have the time and energy to commit to it, because there is a long history, most of it is badly documented, and a lot of it involves subtle abuses.

There is likely to be a resolution soon, one way or another.