It's really two issues - one, there was some disruption and misconduct around the Gender Gap wikiproject that really got overblown a bit and never needed to be an arbitration case to begin with. Granted that some of the participants weren't really contributing in good faith, and that there was a little bit of misunderstanding and overreaction on the part of some who were.
The second issue is that there is a particular person who is an absolutely outstanding article writer, but has a longstanding habit of acting like a jerk on a regular basis. The community and the committee have repeatedly shown themselves to be incapable of finding a solution to that problem, and this is no exception.