Interesting situation. Some folks have suggested that the chairperson should have shut this down. I see this a little differently. In AA, the meeting chairperson is a volunteer service position. Just like every other service position in AA. Now perhaps the AA meetings in our geographic area are different but we often have a shortage of folks who are available to chair meetings. Put a bit differently I have never experienced any form of competition for any service position at any AA meeting I have ever attended. Despite all the AA preaching about how beneficial service positions are to one's recovery we seem to have a shortage of folks with the time and inclination to take all of the service positions at the meetings I attend. So here is a guy/gal who has agreed to lead a meeting and perhaps find new speakers for each meeting. Most of them are in no way qualified to understand how to manage conflicts in the meetings. They just took the service position because they knew the group needed someone and they were willing/available to do so. Each and every one of them have my appreciation and gratitude for taking a service position.
In my view when it comes to unexpected conflicts/problems that occur in an AA meeting we (all of us who are in that meeting) are equally responsible for resolving it. To put this additional burden solely on the poor person who happens to be the volunteer chairperson is just asking too much.