Any WG chair is responsible to report issues seen in session meeting of their list, if he/she is not reporting harassment incidents, then should be removed. All lists of IETF should have one responsible to follow wrong attacks. The IETF should not have any manager or director that does not report harassment (watching is worse).
The chair/AD should try to stop such attacks but if they might not report to solve issue in their social skills still that is wrong, because such behavior has occurred and affected community.
See link in diversity
I will send another comments, sorry for this.
AB